History.

A community was established in Mandaue by a flourishing group of Austronesian people. The Venetian chronicler Antonio Pigafetta wrote of a settlement called misspelled the place Mandani which existed in the area with a chieftain named Apanoaan some called him Lambuzzan in other accounts.  Mandaue natives were forced into a town as decreed by the Spanish authorities. This may have started off as a mission village (which included present day Consolacion, Liloan and Poro) serving as a bulwark for the church in the northern Cebu and was managed by the Jesuit in 1638 then a century later by the Recollects.  The Philippine revolution in 1898 gave the town a new form of administration in accordance with the organic decree of the Central Revolutionary Government. The short-lived revolution was overthrown by the American Troops and a battle nearly destroyed the town in 1901, killing Presidente Benito Ceniza.  Mandaue was a semi-autonomous functioning town. Semi-autonomous as it was still under the jurisdiction of Cebu. Despite having been developed and organized by the Spaniards through-out the ages and its population increasing as the years gone by, the Spaniards did not make an initiative to elevate the town into an independent municipality. It was only after the death of Presidente Ceniza and the establishment of American Rule in Mandaue that the dream of becoming an independent municipality came true. In 1901, Mandaue became an independent municipality.  Mandaue became independent from being an American Commonwealth and a Japanese garrison on July 4, 1946 along with the entire nation. Mandaue became a chartered city on August 30, 1969 and decades later it was recognized as an HUC (Highly Urbanized City) on February 15, 1991. In early-April 2019, Duterte signed a law that declared Mandaue City as a lone legislative district, which means that it will be separated from the sixth district, and will have its own representative of the lone district.

Geography.

The city has a total area of. According to the, the population density is.  The city is the 6th smallest government unit in terms of land area; among the Metro Cebu local government units the city is the second smallest next to the municipality of Cordova in the island of Mactan. The city's land area is only 4.5% of the total land area of Metro Cebu and less than 1% of the total land of the province of Cebu.  The North Reclamation Project, now known as the North Special Administrative Zone, currently has about reclaimed land. Of the 180 hectares, about belong to the city.  It is one of the two (the other one being the municipality of Consolacion) local government units located within the mainland Metro Cebu where the elevation of land is less than.  Many of the areas of the city are extremely flat. About 77.37% is within the 0-8% slope category. Barangays belonging to this region are Centro, Looc, South Special Administrative Zone, Cambaro, Opao, Umapad, Paknaan, Alang-alang, Tipolo, Ibabao, Guizo, Subangdaku, Mantuyong, Maguikay and Tabok. The greater portion of the city, comprising about 70%, is dominated by the Mandaue Clay Loam soil series. This is found in the 0-2% and 2-5% slope ranges. Faraon clay loam characterizes the rest of the land with slope range from 5-8% and up to 25-40%.

Barangays.

Mandaue comprises 27 barangays.

Demographics.

Data showed that the oldest written accounts of Mandaue came from a population of 160 in 1637 to 1638. Mandaue had 10,309 souls according to the. During the first year of its township in 1899, Mandaue had 42 barrios with a population of 21,086. When Mandaue was a second class municipality in 1964 its population was 33,811.  According to the, it has a population of, which is an increase of. Mandaue has a significantly large population at or below the poverty line.

Economy.

About 40 percent of Cebu's export companies are found in Mandaue. The city is dubbed as the industrial hub of Region VII and hosts about 10,000 industrial and commercial businesses, making it a “little rich city” in the country. It is home to some of the world's biggest companies such as San Miguel Corp., Coca-Cola Bottling Corp. and Shemberg, the number one exporter of carrageenan. Mandaue City also accounts for 75 percent of the country's total exports in the furniture sector, making the city the furniture capital of the country.

Tourism.

Mandaue's point of interests, destinations, and attractions include:

Fiestas.

Mandaue Fiesta: Celebrated on May 8 in honor of the patron St. Joseph. Activities that are typically held during this feast are the inter-barangay sports competition, Miss Mandaue ( the longest-running beauty competition in the province), rodeos, street festival, bailes, fairs, and many more.  Panagtagbo sa Mandaue: This is Mandaue's current major festival in honor of the Holy Family. This is celebrated every 3rd week of January on the eve of the"Traslacion" (Transfer of Relic), of one of the significant religious events of the Sinulog Festival which commemorates the union of the Holy Family. In the Translacion, the Santo Niño and Birhen sa Guadelupe come and stay over at the shrine of Saint Joseph in Mandaue for an overnight vigil. This happens on a Friday, and on the early morning of the following Saturday, a fluvial procession is held on Cebu Strait going back to the Minor Basilica. In the festival, there are singing and dancing competitions with a street dancing during the Bibingkahan in honor of Santo Niño. At night, there is a ritual showdown performance which is the highlight of the cultural-religious events.  Kabayo Festival: The Kabayo (Horse) festival also known as Governor's Cup is a horse racing and different equestrian sports with the western way of riding event held annually in the second week of February.  Pasigarbo sa Sugbo: It is a festival showcasing Cebu's culture, faith, history, products, and festivals from each individual town. It is held annually around the 6th of August which is the Charter day of the Province of Cebu. It was formerly held in Mandaue City at the Cebu International Convention Center(CICC), but was transferred to the Cebu City Sports Complex in Cebu City in 2019 due to the abandoned and disrepaired state of the convention center.

Cuisine.

Mandaue has many restaurants which cater to gourmets and international cuisines like Italian, Japanese, Indian, Mediterranean, Lebanese, Arabic, Russian, Korean, Mexican, and Western cuisines. A variety of restaurants also serves meals of local cuisine.  Many famous Cebuano meals like the lechon or "inasal", eaten with achara or pickled vegetables. The "sugba" or barbecue of either "isda" (fish), "baboy" (pork), "manok" (chicken) or "baka" (beef) is found all over Mandaue eaten with "puso", a diamond-shaped hanged rice covered in coco leaves. "Kinilaw" is raw meat usually pork or fish drenched in vinegar and salt. The "buwad" or dried seafood, either fish or squid, can be pungent with a crunchy and chewy texture. There are some exotic meals that can be found like "dinuguan" or pig's blood which is eaten like a soup. Barbecued chicken feet are liked by many locals.  Original cuisine in Mandaue includes "bibingka" which is steamed rice cakes mixed with coconut and sometimes egg. "Binangos" paired with rice is made of ground up corn with Bolinao fish. This dish is found only in Mandaue; other delicacies includes the "tagaktak", the seasonal "buriring" fish (stewed with "iba") and the famous "masareal".

Transportation.

Mandaue City's road network is composed of a national highway which connects the city to its neighboring cities and municipalities, and a national secondary road which traverses the city's metropolitan area. The total length of the city road network (paved and unpaved) and the four bridges, is about, broken down into:  Road density is of land. In terms of population, road density is per one thousand inhabitants.  Land transportation is being served by PUJ, utility vehicles, mini-buses, multi-cabs, tricycles, trisikads and for cargoes, trailers and vans. Sea transport of Mandaue is highly dependent on Port of Cebu and Cebu International Port, because of the city's proximity to these facilities.

Education.

Mandaue houses two universities, the Cebu Doctors' University and the Lapu-Lapu–Mandaue campus of the University of Cebu. There are also technical schools like TESDA in barangays Banilad and Looc and other private institutions that provide certificate degrees. Associate degree, Baccalaureate Degrees, Master's and Doctoral programs.  Mandaue has institutionalized learning with the Cabahug Medal which was started on 1923 by Sotero Cabahug as a medal of academic excellence annually. The Mandaue Fraternal Society was also created in the early part of the 19th century to provide a community for the professionals during the time when Mandaue was still a sleepy town.  Cebu's part-time Japanese school, the Cebu Japanese School (CJS; セブ補習授業校 "Sebu Hoshū Jugyō Kō"), is located on the fifth floor of the Clotilde Commercial Center in Barangay Casuntingan, Mandaue City.

Media.

Television.

Television stations based in Mandaue City:

Radio.

Radio stations licensed in Mandaue City:

', officially the'(; ) or simply known as City, is a highly urbanized city in the island province of Cebu in the region of Central Visayas,. According to the, it has a population of people.

曼达维市(又译曼达威市或万那威市;英语:Mandaue City)是菲律宾宿务省的第一级城市,被认为是「宿务岛的心脏地带」,也是约1万家商业机构的所在地。宿务省有两个高度都市化城市,一个是曼达维市是,另一个是首府宿务市──两个城市位置贴近,组成了宿务都会区的核心地带。


History.

In July 2010, Rackspace Hosting and NASA jointly launched an open-source cloud-software initiative known as OpenStack. The mission statement was "to produce the ubiquitous Open Source Cloud Computing platform that will meet the needs of public and private clouds regardless of size, by being simple to implement and massively scalable".  The OpenStack project intended to help organizations offer cloud-computing services running on standard hardware. The community's first official release, code-named Austin, appeared three months later on, with plans to release regular updates of the software every few months. The early code came from NASA's Nebula platform as well as from Rackspace's Cloud Files platform. The original cloud architecture was designed by the NASA Ames Web Manager, Megan A. Eskey, and was a 2009 open source architecture called OpenNASA v2.0. The cloud stack and open stack modules were merged and released as open source by the NASA Nebula team in concert with Rackspace.  In 2011, developers of the Ubuntu Linux distribution adopted OpenStack with an unsupported technology preview of the OpenStack "Bexar" release for Ubuntu 11.04 "Natty Narwhal". Ubuntu's sponsor Canonical then introduced full support for OpenStack clouds, starting with OpenStack's Cactus release.  OpenStack became available in Debian Sid from the Openstack "Cactus" release in 2011, and the first release of Debian including OpenStack was Debian 7.0 (code name "Wheezy"), including OpenStack 2012.1 (code name: "Essex").  In October 2011, SUSE announced the public preview of the industry's first fully configured OpenStack powered appliance based on the "Diablo" OpenStack release. In August 2012, SUSE announced its commercially supported enterprise OpenStack distribution based on the "Essex" release.  In November 2012, The UK's Government Digital Service (GDS) launched Inside Government based on the OpenNASA v2.0 Government as a Platform (GaaP) model. In 2012, Red Hat announced a preview of their OpenStack distribution, beginning with the "Essex" release. After another preview release, Red Hat introduced commercial support for OpenStack with the "Grizzly" release, in July 2013.  The OpenStack organization has grown rapidly and is supported by more than 540 companies.  In 2012 NASA withdrew from OpenStack as an active contributor, and instead made the strategic decision to use Amazon Web Services for cloud-based services. In July 2013, NASA released an internal audit citing lack of technical progress and other factors as the agency's primary reason for dropping out as an active developer of the project and instead focus on the use of public clouds. This report is contradicted in part by remarks made by Ames Research Center CIO, Ray O'Brien.  In December 2013, Oracle announced it had joined OpenStack as a Sponsor and planned to bring OpenStack to Oracle Solaris, Oracle Linux, and many of its products. It followed by announcing Oracle OpenStack distributions for Oracle Solaris and for Oracle Linux using Icehouse on 24 September 2014.  In May 2014, HP announced HP Helion and released a preview of HP Helion OpenStack Community, beginning with the IceHouse release. HP has operated HP Helion Public Cloud on OpenStack since 2012.  At the 2014 Interop and Tech Field Day, software-defined networking was demonstrated by Avaya using Shortest path bridging and OpenStack as an automated campus, extending automation from the data center to the end device, removing manual provisioning from service delivery.  As of March 2015, NASA still makes use of OpenStack private cloud and has RFPs out for OpenStack public cloud support.

Historical names.

Several OpenStack projects changed names due to trademark issues.

OpenStack development.

The OpenStack community collaborates around a six-month, time-based release cycle with frequent development milestones.  During the planning phase of each release, the community would gather for an OpenStack Design Summit to facilitate developer working sessions and to assemble plans. These Design Summits would coincide with the OpenStack Summit conference.  Starting with the Pike development cycle the design meetup activity has been separated out into a separate Project Teams Gathering (PTG) event. This was done to avoid the developer distractions caused by presentations and customer meetings that were happening at the OpenStack Summit and to allow the design discussions to happen ahead of the start of the next cycle.  Recent OpenStack Summits have taken place in Shanghai on 4-6 November 2019, Denver on 29 April-1 May 2019, Berlin on 13-19 November 2018, Vancouver on 21-25 May 2018, Sydney on 6-8 November 2017, Boston on 8-11 May 2017, Austin on 25–29 April 2016, and Barcelona on 25–28 October 2016. Earlier OpenStack Summits have taken place also in Tokyo in October 2015, Vancouver in May 2015, and Paris in November 2014. The summit in May 2014 in Atlanta drew 4,500 attendees — a 50% increase from the Hong Kong summit six months earlier.

Components.

OpenStack has a modular architecture with various code names for its components.

Compute (Nova).

Nova is the OpenStack project that provides a way to provision compute instances (aka virtual servers). Nova supports creating virtual machines, baremetal servers (through the use of ironic), and has limited support for system containers. Nova runs as a set of daemons on top of existing Linux servers to provide that service. Nova is written in Python. It uses many external Python libraries such as Eventlet (concurrent networking library), Kombu (AMQP messaging framework), and SQLAlchemy (SQL toolkit and Object Relational Mapper). Nova is designed to be horizontally scalable. Rather than switching to larger servers, you procure more servers and simply install identically configured services.  Due to its widespread integration into enterprise-level infrastructures, monitoring OpenStack performance in general, and Nova performance in particular, scaling has become an increasingly important issue. Monitoring end-to-end performance requires tracking metrics from Nova, Keystone, Neutron, Cinder, Swift and other services, in addition to monitoring RabbitMQ which is used by OpenStack services for message passing. All these services generate their own log files, which, especially in enterprise-level infrastructures, also should be monitored.

Networking (Neutron).

Neutron is an OpenStack project to provide “network connectivity as a service” between interface devices (e.g., vNICs) managed by other OpenStack services (e.g., nova). It implements the OpenStack Networking API.  It manages all networking facets for the Virtual Networking Infrastructure (VNI) and the access layer aspects of the Physical Networking Infrastructure (PNI) in the OpenStack environment. OpenStack Networking enables projects to create advanced virtual network topologies which may include services such as a firewall, and a virtual private network (VPN).  Neutron allows dedicated static IP addresses or DHCP. It also allows Floating IP addresses to let traffic be dynamically rerouted.  Users can use software-defined networking (SDN) technologies like OpenFlow to support multi-tenancy and scale. OpenStack networking can deploy and manage additional network services—such as intrusion detection systems (IDS), load balancing, firewalls, and virtual private networks (VPN).

Block storage (Cinder).

Cinder is the OpenStack Block Storage service for providing volumes to Nova virtual machines, Ironic bare metal hosts, containers and more. Some of the goals of Cinder are to be/have:  Cinder volumes provide persistent storage to guest virtual machines - known as instances, that are managed by OpenStack Compute software. Cinder can also be used independent of other OpenStack services as stand-alone software-defined storage. The block storage system manages the creation,replication, snapshot management, attaching and detaching of the block devices to servers.

Identity (Keystone).

Keystone is an OpenStack service that provides API client authentication, service discovery, and distributed multi-tenant authorization by implementing OpenStack's Identity API. It is the common authentication system across the cloud operating system. Keystone can integrate with directory services like LDAP. It supports standard username and password credentials, token-based systems and AWS-style (i.e. Amazon Web Services) logins. The OpenStack keystone service catalog allows API clients to dynamically discover and navigate to cloud services.

Image (Glance).

The Image service (glance) project provides a service where users can upload and discover data assets that are meant to be used with other services. This currently includes images and metadata definitions.

Images.

Glance image services include discovering, registering, and retrieving virtual machine (VM) images. Glance has a RESTful API that allows querying of VM image metadata as well as retrieval of the actual image. VM images made available through Glance can be stored in a variety of locations from simple filesystems to object-storage systems like the OpenStack Swift project.

Metadata Definitions.

Glance hosts a metadefs catalog. This provides the OpenStack community with a way to programmatically determine various metadata key names and valid values that can be applied to OpenStack resources.

Object storage (Swift).

Swift is a distributed, eventually consistent object/blob store. The OpenStack Object Store project, known as Swift, offers cloud storage software so that you can store and retrieve lots of data with a simple API. It's built for scale and optimized for durability, availability, and concurrency across the entire data set. Swift is ideal for storing unstructured data that can grow without bound.  In August 2009, Rackspace started the development of the precursor to OpenStack Object Storage, as a complete replacement for the "Cloud Files" product. The initial development team consisted of nine developers. SwiftStack, an object storage software company, is currently the leading developer for Swift with significant contributions from Intel, Red Hat, NTT, HP, IBM, and more.

Dashboard (Horizon).

Horizon is the canonical implementation of OpenStack's Dashboard, which provides a web based user interface to OpenStack services including Nova, Swift, Keystone, etc. Horizon ships with three central dashboards, a “User Dashboard”, a “System Dashboard”, and a “Settings” dashboard. Between these three they cover the core OpenStack applications and deliver on Core Support. The Horizon application also ships with a set of API abstractions for the core OpenStack projects in order to provide a consistent, stable set of reusable methods for developers. Using these abstractions, developers working on Horizon don't need to be intimately familiar with the APIs of each OpenStack project.

Orchestration (Heat).

Heat is a service to orchestrate multiple composite cloud applications using templates, through both an OpenStack-native REST API and a CloudFormation-compatible Query API.

Workflow (Mistral).

Mistral is a service that manages workflows. User typically writes a workflow using workflow language based on YAML and uploads the workflow definition to Mistral via its REST API. Then user can start this workflow manually via the same API or configure a trigger to start the workflow on some event.

Telemetry (Ceilometer).

OpenStack Telemetry (Ceilometer) provides a Single Point Of Contact for billing systems, providing all the counters they need to establish customer billing, across all current and future OpenStack components. The delivery of counters is traceable and auditable, the counters must be easily extensible to support new projects, and agents doing data collections should be independent of the overall system.

Database (Trove).

Trove is a database-as-a-service provisioning relational and a non-relational database engine.

Elastic map reduce (Sahara).

Sahara is a component to easily and rapidly provision Hadoop clusters. Users will specify several parameters like the Hadoop version number, the cluster topology type, node flavor details (defining disk space, CPU and RAM settings), and others. After a user provides all of the parameters, Sahara deploys the cluster in a few minutes. Sahara also provides means to scale a preexisting Hadoop cluster by adding and removing worker nodes on demand.

Bare metal (Ironic).

Ironic is an OpenStack project that provisions bare metal machines instead of virtual machines. It was initially forked from the Nova Baremetal driver and has evolved into a separate project. It is best thought of as a bare-metal hypervisor API and a set of plugins that interact with the bare-metal hypervisors. By default, it will use PXE and IPMI in concert to provision and turn on and off machines, but Ironic supports and can be extended with vendor-specific plugins to implement additional functionality.

Messaging (Zaqar).

Zaqar is a multi-tenant cloud messaging service for Web developers. The service features a fully RESTful API, which developers can use to send messages between various components of their SaaS and mobile applications by using a variety of communication patterns. Underlying this API is an efficient messaging engine designed with scalability and security in mind. Other OpenStack components can integrate with Zaqar to surface events to end users and to communicate with guest agents that run in the "over-cloud" layer.

Shared file system (Manila).

OpenStack Shared File System (Manila) provides an open API to manage shares in a vendor agnostic framework. Standard primitives include ability to create, delete, and give/deny access to a share and can be used standalone or in a variety of different network environments. Commercial storage appliances from EMC, NetApp, HP, IBM, Oracle, Quobyte, INFINIDAT and Hitachi Data Systems are supported as well as filesystem technologies such as Red Hat GlusterFS or Ceph.

DNS (Designate).

Designate is a multi-tenant REST API for managing DNS. This component provides DNS as a Service and is compatible with many backend technologies, including PowerDNS and BIND. It doesn't provide a DNS service as such as its purpose is to interface with existing DNS servers to manage DNS zones on a per tenant basis.

Search (Searchlight).

Searchlight provides advanced and consistent search capabilities across various OpenStack cloud services. It accomplishes this by offloading user search queries from other OpenStack API servers by indexing their data into ElasticSearch. Searchlight is being integrated into Horizon and also provides a Command-line interface.

Key manager (Barbican).

Barbican is a REST API designed for the secure storage, provisioning and management of secrets. It is aimed at being useful for all environments, including large ephemeral Clouds.

Container orchestration (Magnum).

Magnum is an OpenStack API service developed by the OpenStack Containers Team making container orchestration engines such as Docker Swarm, Kubernetes, and Apache Mesos available as first class resources in OpenStack. Magnum uses Heat to orchestrate an OS image which contains Docker and Kubernetes and runs that image in either virtual machines or bare metal in a cluster configuration.

Root Cause Analysis (Vitrage).

Vitrage is the OpenStack RCA (Root Cause Analysis) service for organizing, analyzing and expanding OpenStack alarms & events, yielding insights regarding the root cause of problems and deducing their existence before they are directly detected.

Rule-based alarm actions (Aodh).

This alarming service enables the ability to trigger actions based on defined rules against metric or event data collected by Ceilometer or Gnocchi.

Compatibility with other cloud APIs.

OpenStack does not strive for compatibility with other clouds' APIs. However, there is some amount of compatibility driven by various members of the OpenStack community for whom such things are important.

Governance.

OpenStack is governed by a non-profit foundation and its board of directors, a technical committee, and a user committee. The board of directors is made up of eight members from each of the eight platinum sponsors, eight members from the 24 defined maximum allowed Gold sponsors, and eight members elected by the Foundation individual members.

Appliances.

An OpenStack Appliance is the name given to software that can support the OpenStack cloud computing platform on either physical devices such as servers or virtual machines or a combination of the two. Typically a software appliance is a set of software capabilities that can function without an operating system. Thus, they must contain enough of the essential underlying operating system components to work. Therefore, a strict definition might be: an application that is designed to offer OpenStack capability without the necessity of an underlying operating system. However, applying this strict definition may not be helpful, as there is not really a clear distinction between an appliance and a distribution. It could be argued that the term appliance is something of a misnomer because OpenStack itself is referred to as a cloud operating system so using the term OpenStack appliance could be a misnomer if one is being pedantic.  If we look at the range of Appliances and Distributions one could make the distinction that distributions are those toolsets which attempt to provide a wide coverage of the OpenStack project scope, whereas an Appliance will have a more narrow focus, concentrating on fewer projects. Vendors have been heavily involved in OpenStack since its inception, and have since developed and are marketing a wide range of appliances, applications and distributions.

Vendors.

A large number of vendors offer OpenStack solutions, meaning that an organization wishing to deploy the technology has a complex task in selecting the vendor offer that best matches its business requirements. Barb Darrow offered this overview in Fortune on 27 May 2015, pointing out that there may be some consolidation in the market that will clarify those decisions.  There are other aspects that users need to consider, for example, the real costs involved. Some vendors will make an offer which encompasses most of the OpenStack projects; others will only offer certain components. Other considerations include the extent of proprietary code used to manage a lack of maturity in an OpenStack component, and to what extent that encourages vendor lock-in.  The most authoritative information on vendor products is at the OpenStack Foundation website.

Challenges to implementation.

OpenStack is a complex entity, and adopters face a range of challenges when trying to implement OpenStack in an organisation. For many organisations trying to implement their own projects, a key issue is the lack of skills available. In an article on "The New Stack", Atul JHA identifies five challenges any organization wishing to deploy OpenStack will face.

Installation challenges.

OpenStack is a suite of projects rather than a single product, and because each of the various applications needs to be configured to suit the user's requirements, installation is complex and requires a range of complementary skill-sets for an optimum set-up. One obvious solution would be to take a complete vendor supplied package containing hardware and software, although due diligence is essential.

Documentation.

This is more a function of the nature of documentation with open source products than OpenStack per se, but with more than 25 projects, managing document quality is always going to be challenging.

Upgrading OpenStack.

One of the main objectives of using cloud type infrastructure is that it offers its users not only high reliability but also high availability, something that public cloud suppliers will offer in Service Level Agreements.  Due to OpenStack's multi-project development approach, the complexity involved in synchronising the different projects during an upgrade implementation may mean that downtime is unavoidable"."

Long term support.

It's quite common for a business to keep using an earlier release of software for some time after it has been upgraded. The reasons for this are pretty obvious and referred to above. However, there is little incentive for developers in an open source project to provide support for superseded code. In addition, OpenStack itself has formally discontinued support for some old releases.  Given the above challenges the most appropriate route for an organization wishing to implement OpenStack would be to go with a vendor, and source an OpenStack appliance or distribution.

Users.

OpenStack has a wide variety of users, from a number of different sectors. Notable users include:

Deployment models.

As the OpenStack project has matured, vendors have pioneered multiple ways for customers to deploy OpenStack:

OpenStack is a free open standard cloud computing platform, mostly deployed as infrastructure-as-a-service (IaaS) in both public and private clouds where virtual servers and other resources are made available to users. The software platform consists of interrelated components that control diverse, multi-vendor hardware pools of processing, storage, and networking resources throughout a data center. Users either manage it through a web-based dashboard, through command-line tools, or through RESTful web services.

OpenStack是美国太空总署和Rackspace合作研发的云端运算软件,以Apache授权条款授权,并且是自由和开放源代码软件。


Nomenclature and history.

Kepler-11 and its planets were discovered by NASA's Kepler Mission, a mission tasked with discovering planets in transit around their stars. The transit method that Kepler uses involves detecting dips in brightness in stars. These dips in brightness can be interpreted as planets whose orbits move in front of their stars from the perspective of Earth. Kepler-11 is the first discovered exoplanetary system with more than three transiting planets.  Kepler-11 is named for the Kepler Mission: it is the 11th star with confirmed planets discovered in the Kepler field of view. The planets are named alphabetically, starting with the innermost: "b", "c", "d", "e", "f", and "g", distinguishers that are tagged onto the name of their home star.

Characteristics.

Kepler-11 is a G-type star that is approximately 104% the mass of and 102% the radius of the Sun. It has a surface temperature of about 5836 K and is estimated to have an age of around 3.2 billion years. In comparison, the Sun is about 4.6 billion years old and has a surface temperature of 5778 K.  With an apparent magnitude of 14.2, it is too faint to be seen with the naked eye.

Planetary system.

All known planets transit the star; this means that all six planets' orbits appear to cross in front of their star as viewed from the Earth's perspective. Their inclinations relative to Earth's line of sight, or how far above or below the plane of sight they are, vary by a little more than a degree. This allows direct measurements of the planets' periods and relative diameters (compared to the host star) by monitoring each planet's transit of the star. Simulations suggest that the mean mutual inclinations of the planetary orbits are about 1°, meaning the system is probably more coplanar (flatter) than the Solar System, where the corresponding figure is 2.3°.  The estimated masses of planets "b" - "f" fall in the range between those of Earth and Neptune. Their estimated densities, all lower than that of Earth, imply that none of them have an Earth-like composition; a significant hydrogen/helium atmosphere is predicted for planets "c", "d", "e", "f", and "g", while planet "b" may be surrounded by a steam atmosphere or perhaps by a hydrogen atmosphere. The low densities likely result from high-volume extended atmospheres that surround cores of iron, rock, and possibly HO. The inner constituents of the Kepler-11 system were, at the time of their discoveries, the most comprehensively understood extrasolar planets smaller than Neptune. Currently, observations do not place a firm constraint on the mass of planet "g" (<25 M). However, formation and evolution studies indicate that the mass of planet "g" is not much greater than about 7 M.  Kepler-11 planets may have formed "in situ" (i.e., at their observed orbital locations) or may have started their formation farther away from the star while migrating inward through gravitational interactions with a gaseous protoplanetary disk. This second scenario predicts that a substantial fraction of the planets' mass is in HO. Regardless of the formation scenario, the gaseous component of the planets accounts for less than about 20% of their masses but for ≈40 to ≈60% of their radii. In 2014, the dynamical simulation shown what the Kepler-11 planetary system have likely to undergone a substantial inward migration in the past, producing an observed pattern of lower-mass planets on tightest orbits.  The system is among the most compact known; the orbits of planets "b" - "f" would easily fit inside the orbit of Mercury, with "g" only slightly outside it. Despite this close packing of the orbits, dynamical integrations indicate the system has the potential to be stable on a time scale of billions of years. The planetary system of Kepler-11 currently may be on the verge of instability though.  None of the planets are in low-ratio orbital resonances, in which multiple planets gravitationally tug on and stabilize each other's orbits, resulting in simple ratios of their orbital periods. However, "b" and "c" are close to a 5:4 ratio.  There could conceivably be other planets in the system that do not transit the star, but they would only be detectable by the effects of their gravity on the motion of the visible planets (much as how Neptune was discovered).

Kepler-11, also designated as 2MASS J19482762+4154328, is a Sun-like star slightly larger than the Sun in the constellation Cygnus, located some 2,150 light years from Earth. It is located within the field of vision of the Kepler spacecraft, the satellite that NASA's Kepler Mission uses to detect planets that may be transiting their stars. Announced on February 2, 2011, the star system is among the most compact and flattest systems yet discovered. It is the first discovered case of a star system with six transiting planets. All discovered planets are larger than Earth, with the larger ones being about Neptune's size.

开普勒11()是一颗类似太阳的恒星,位于天鹅座内,距离地球约2,000光年。这颗星是由开普勒太空望远镜发现,并由美国航空航天局于2011年2月2日公布。开普勒11是首个被确定拥有6颗行星的恒星。所有开普勒11的行星质量均介于地球与海王星之间。


History.

The church of the was built by order of Queen Anne of Austria, wife of Louis XIII. After the birth of her son Louis XIV, Anne (previously childless after 23 years of marriage) showed her gratitude to the Virgin Mary by building a church on the land of a Benedictine convent. Louis XIV himself is said to have laid the cornerstone for the in a ceremony that took place April 1, 1645, when he was seven years old.  The church of the Val-de-Grâce, designed by and, is considered by some as Paris's best example of baroque architecture (curving lines, elaborate ornamentation, and harmony of different elements). Construction began in 1645, and was completed in 1667.  The Benedictine nuns provided medical care for injured revolutionaries during the French Revolution, and thus the church at was spared much of the desecration and vandalism that plagued other, more famous Paris churches (for example, was looted and turned into a warehouse, and was used as a barn). As a result, the church's exquisite interior is one of the few unspoiled remnants of Paris's pre-Revolution grandeur. Following the Revolution, the buildings were converted into a military hospital.  Currently, the original buildings only serve for offices and teaching facilities (""); the actual medical facilities are inside a large modern building to the east on the same grounds.  The present-day hospital was built in the 1970s and completed in 1979. It has a capacity of 350 beds, in various specialties. The hospital is accessible to military personnel in need of medical aid as well as to any person with health coverage under the French social security system. It is famous for being the place where the top officials of the French Republic generally get treated for ailment.  The statue standing in the courtyard is that of (as sculpted by in 1843), who was Napoleon's personal surgeon and innovator of the concept of battlefield triage.  The old abbey alongside the church is now a museum of French army medicine. Tours of the museum and church are available for a small fee (being a military facility, the grounds are under military guard and tourists are escorted). Cameras are not permitted except for inside the church itself.  The last emperor of Vietnam,, died at hospital on July 30, 1997, aged 83.

People buried at Val-de-Grâce.

was later the traditional burial place for members of the House of Orléans, cadet of the House of Bourbon:

Impact on the arts.

During World War I, and, surrealist artists, were enlisted as physicians-in-training at the hospital. As a part of the French government's efforts to keep morale up during the war, a museum of reconstructive surgery was built in the hospital. The exhibits consisted of wax sculptures of deformed human faces and the results of reconstructive surgery. A look at the museum reveals that there is almost no doubt that the exhibits influenced the two artists and eventually the surrealist movement, which frequently deals with themes of dismemberment and disfigurement. The hospital was featured in the motion picture "Lucy" starring Scarlett Johansson. (https://www.imdb.com/title/tt2872732/locations)

The'(' or ") was a military hospital located at in the 5th arrondissement of Paris, France. It was closed as a hospital in 2016.

圣宠谷(Val-de-Grâce)是法国首都巴黎第五区的一所军医院。


Geography.

The Goldfields-Esperance region is the largest of Western Australia's regions, with an area of, larger than the U.S. state of Texas. It is mostly a low and flat plateau of extremely ancient Precambrian rocks that have been stable since long before the Paleozoic Era. Because of the extreme geological stability and the absence of glaciation since the Carboniferous, the soils are extremely infertile and generally quite saline. Consequently, the region supports the lowest stocking rates in the world: it is considered that one sheep per square mile is the maximum sustainable rate except in the small wetter area near Esperance. There are no rivers; any rainfall that is not absorbed by the dense rooting systems of the native flora percolates to form extremely saline groundwater, which is very frequently too salty even for adult sheep.

Climate.

The climate is mostly hot and dry. Annual rainfall is typically around per year and can be very variable, except in the small area near Esperance and Cape Arid National Park where reliable winter rainfall can give annual totals as high as 635 mm (25 inches) falling mainly in the winter months. Most rainfall is produced by thunderstorms in spring or summer or by cloudbands from the northwest in autumn and winter, but sometimes cyclones from the Pilbara decay into rain depressions and produce heavy rainfall. Climate change has already had a major impact: in the Kalgoorlie – Eucla – Wiluna – Giles area annual rainfall has increased by over 40 percent since 1967 – probably due to lower frequencies of anticyclones located over the interior of Australia instead of the adjacent oceans.  The Little Sandy Desert and the Gibson Desert are found in the northern part of the region, with the Great Victoria Desert in the south east.  It has a population of just under 60,000 people, about half of whom live in the City of Kalgoorlie-Boulder. Another quarter live in the Shire of Esperance, and the remaining shires are very sparsely populated. Nearly 10% of the region's population are of Aboriginal descent, which is substantially higher than the state as a whole.

Economy.

The economy of the Goldfields sub-region is based on the extraction and processing of various mineral resources, primarily gold and nickel. In 2012 the mining of gold, nickel and platinum yielded just under 9 billion.  Pastoralism in the northern goldfields commenced in the early 1900s with Yundamindera Station being established by Dr. Laver. In 1923 Yundmindera was purchased along with Mount Celia Station with a combined area of over by T. H. Pearse, who stocked the property with sheep. Between 1925 and 1928 were established, and over £1,500,000 was invested in properties in the northern and eastern goldfields. In three months of 1925 over 40,000 sheep were railed to the area and in one month of 1927 seven trains carrying sheep arrived. By 1934 the goldfields were stocked with over 500,000 sheep and 25,000 cattle. Shearing the same year produced approximately 11,667 bales of wool valued at £243,600.  Further south near Esperance, the economy is based on agriculture, with wheat, canola and barley widely grown and making up about 80% of the area's agricultural economy. These crops require huge inputs of fertilisers because of the sandy nature of the soils and are a major threat to the region's great plant diversity. Pastoralism is also common, with both sheep and cattle stations being common in the area. Along the coast fishing and aquaculture are common, with fisheries for abalone, pilchards and sharks.

<mapframe text="Location of Goldfields-Esperance region in Western Australia." width="300" height="500" zoom="4" latitude="-29" longitude="124.9"> </mapframe>

金矿-斯佩兰斯区(英语:Goldfields-Esperance)是九个西澳大利亚地区的其中一个。金矿-斯佩兰斯区位于西澳大利亚州的东南方,是西澳中最大的行政区。


History.

The club was founded on 20 August 1920, when they participated in a colonial competition in Osorno. It was founded by a group of Palestinian immigrants; the name of the club reflects the origin in Chile's Palestinian community. In 1952 the Federación de Fútbol de Chile set up the first professional leagues. Palestino was accepted into the Second Division, which they won to ascertain promotion to the Primera División.  In 1955 the club won their first national championship under the coaching of Argentine captain "Guillermo Coll", in that era the club became known by the nickname "millonario" (Millionaire) because of their ability to attract top class footballers.  In 1978 the club won their second league title, this time the team was led by Chilean captain Elías Figueroa. In this campaign they set a new record in the domestic tournament, for the number of games unbeaten and soon won the Copa Chile to claim the league and cup double.  In 2004 the club became a registered company, but the change of status did not bring the expected improvement in results. In 2006 they finished in 18th place out of 20 teams, forcing them to face a play-off against Fernandez Vial to keep their place in the top flight. Ultimately the club would triumph thus preserving their spot within the Chilean first division.  The club made a surprising run to the final of the Clausura 2008 tournament, where they lost to champions Colo-Colo. Following this success, the club intends to float on the Chilean and Palestinian stock exchanges.  In January 2014, Palestino was fined the equivalent of $1,300 for using a new team jersey in the club's traditional colors, red, green and black, but with the number one in the squad numbers on the back shaped as the map of Palestine prior to the creation of Israel in 1948. Chilean Jewish groups complained about the political significance of this, with a formal complaint to their national Federation being made by Patrick Kiblisky, owner of first-division club Ñublense. The jerseys were said to have been first used in December 2013, although the club said they were used in the prior season. The federation banned the club from using the map on the back of the shirts and imposed a fine on the club on the grounds that the Federation is opposed to "any form of political, religious, sexual, ethnic, social or racial discrimination". On its Facebook page, the club stated: "For us, free Palestine will always be historical Palestine, nothing less."

Honours.

Primera División  Copa Chile  Primera B

Women's team.

The Palestino women's team plays in the Campeonato Nacional Primera División de Fútbol Femenino, the top women's football competition in Chile. In 2015 they won the Clausura tournament, thus ending a ten-season title streak by Colo-Colo. The captain, Ashraf Khatib, lifted the title. She was quoted as saying it was a pleasure to be the first actual Palestinian woman to lift the title in Chile. Former Palestino forward María José Urrutia was a member of the Chile women's national football team for the 2019 FIFA Women's World Cup. With a header against Thailand in Chile's 2-0 win in the group stage, she became the first Chilean player to score a goal in the FIFA Women's World Cup. Former Palestino defender Javiera Toro was also a member of the Chilean team at the 2019 tournament.

Club Deportivo Palestino is a professional football club based in the city of Santiago, Chile. The club was founded in 1920 and plays in the Primera División de Chile. They play their home games at the Estadio Municipal de La Cisterna stadium, which has a capacity of approximately 8,000 seats.

帕莱斯蒂诺体育俱乐部(),又译作巴勒斯坦人体育俱乐部,是智利足球俱乐部,位于首都圣地亚哥,俱乐部现为智利足球甲级联赛球队。主体育场为拉希斯特纳市政体育场(Estadio Municipal de La Cisterna),拥有约 12,000 个座位。


Plot summary.

Detective Elijah Baley of Earth is training with his son and others to overcome their socially ingrained agoraphobia when he is told that the Spacer world of Aurora has requested him to investigate a crime: the destruction of the mind of R. Jander Panell, a humaniform robot identical to R. Daneel Olivaw, with a mental block. The robot's inventor, Han Fastolfe, has admitted that he is the only person with the skill to have done this, but denies having done so. Fastolfe is also a prominent member of the Auroran political faction that favors Earth; therefore, it is politically expedient that he be exonerated. En route to Aurora, Baley again is partnered with R. Daneel Olivaw, and introduced to R. Giskard Reventlov, a robot of an earlier model.  On Aurora, he interviews Gladia Delmarre, R. Jander's last owner, and discovers that Gladia had a sexual relationship with Jander, to the point of considering him husband in an emotional sense. Baley later interviews Fastolfe's estranged daughter, Vasilia Fastolfe (alias "Vasilia Aliena"), who claims that her father would do anything necessary to advance psychohistory, including the incapacitation of Jander and Gladia's heartbreak. Following that, Baley interviews Santirix Gremionis, an Auroran who, with both Gladia and Vasilia, committed the Auroran taboo of offering himself repeatedly (sexually) after rejection. Gremionis denies involvement in the murder, and says he has reported Baley to the Chairman (the executive of the Auroran Government) for slander; but realizes, upon questioning, that Vasilia arranged his infatuation with Gladia.  Next, Baley interviews Kelden Amadiro, Fastolfe's chief political rival and head of the Robotics Institute, who explains the Institute's political motivations: that they wish to see Aurora alone colonize the Galaxy, by means of humaniform robots which at present only Fastolfe can build. On the way from the interview with Amadiro, Baley's airfoil (a personal hovercraft) is forced to stop. The air compressor has been sabotaged. Baley, suspecting Amadiro, orders Daneel and Giskard to flee. When several robots catch up with the car and question Baley, Baley tells them that he ordered Daneel back to the Robotics Institute, and they leave. Baley flees the car into the thunderstorm outside, where his agoraphobia renders him unconscious. He is recovered by Gladia and Giskard, and taken to Gladia's house. At an earlier-arranged meeting with the Chairman, Fastolfe, and Amadiro, Baley accuses Amadiro of sabotaging the car so that he could keep him, helpless, in the Institute, and thus have a legitimate reason to have Daneel there as well, unsupervised. As Baley states, without Fastolfe's cooperation, the only way to obtain knowledge about humaniform robots is to reverse engineer Daneel by thorough questioning, which would have allowed Amadiro to learn the details of his workings.  While logically consistent, Baley's unsupported accusation cannot stand against a formal denial by an Auroran as prominent and respected as Amadiro. However, Baley then confronts Amadiro with the revelation that Amadiro knew of the relationship between Gladia and Jander, and moreover, of her considering him her husband; something quite unthinkable for a native Auroran. Amadiro says he may have heard it from someone, but cannot remember whom.  Baley then states that only one Auroran could have told Amadiro about the relationship: Jander himself. Then, he gives the solution to the mystery: that in Gladia's absence, Amadiro questioned and tested Jander via trimensional viewing (telepresence). Daneel was part of Fastolfe's establishment, and thus well guarded, but Jander was at the house of the much less skilled Gladia, thus questioning him for reverse engineering purposes was much easier. Gremionis was encouraged to court Gladia because they tended to take long walks together, allowing Amadiro more time for his testing. The sabotage to the car was intended to capture Daneel and complete the analysis.  When Baley states that these experiments might have accidentally led to Jander's deactivation, Amadiro snaps and states the experiments were completely harmless. Thus, he effectively admits he was working with Jander, which makes his situation hopeless. As a result, he is forced to compromise with Fastolfe's policies; Amadiro agrees with Earth's right to share in the galactic colonization, while Fastolfe gives the Institute his data about humaniform robot design. Baley, however, confronts Giskard, who admits that Vasilia unknowingly gave him telepathic abilities during experiments when she was a child. Using knowledge derived from Han Fastolfe's mind, Giskard shut down Jander, to thwart Amadiro's attempt to build humaniform robots. Giskard allows Baley to retain knowledge of his abilities, but prevents him (with the help of his telepathic abilities) from revealing the secret.

Characters.

Below is a list of all the major and minor characters in the book, in order of appearance, with plot detail.

The Robots of Dawn is a "whodunit" science fiction novel by American writer Isaac Asimov, first published in 1983. It is the third novel in Asimov's "Robot" series.

《曙光中的机器人》(The Robots of Dawn),是美国作家以撒·艾西莫夫(Isaac Asimov)出版于1983年的科幻小说,第三部以以利亚·贝莱(Elijah Baley)为主角的科幻推理小说,艾西莫夫以实例说明科幻小说有多种可能发展性,不必自我设限。这部小说在1984年荣获雨果奖(Hugo Award)最佳长篇小说提名。


Botanical description.

The petai tree can grow to about 30 metres. It bears flowers in a light bulb-shaped mass at the end of long stalks. The flowers secrete a nectar that attracts bats and other pollinators. The fruits emerge as long, twisted, translucent pods in a cluster of seven or eight pods. When those pods are mature, within them will reside the petai beans or seeds.

Use in cooking.

The beans of other "Parkia" species ("Parkia javanica" and "Parkia singalaris" for example) are also popular as culinary ingredient in Indonesia, Malaysia, Singapore, Brunei, Laos, southern Thailand, Burma, and northeastern India specially Nagaland,Manipur and Mizoram, and are sold in bunches, still in the pod, or the seeds are sold in plastic bags. Pods are gathered from the wild, or from cultivated trees: they are exported in jars or cans, pickled in brine, or frozen.  It is known as "petai", "pete" in Indonesia, Malaysia and Singapore. In marketplace, depending on the country of origin "Parkia" species may be labelled "wakerec", "petai", "yongchak", in Thadou "Jonglha" (pronounced zong-lha). They are best when combined with other strongly flavoured foods such as garlic, chili peppers, dried shrimp or shrimp paste, as in sambal petai. When young, the pods are flat because the seeds have not yet developed, and they hang like a bunch of slightly twisted ribbons, pale green, almost translucent. At this stage they may be eaten raw, fried or pickled. Young tender pods with undeveloped beans can be used whole in stir-fried dishes.  The seeds are also dried and seasoned for later consumption. When dried the seeds turn black. Petai beans or seeds look like broad beans. Like mature broad beans, they may have to be peeled before cooking. Petai has earned its nickname'stink bean' because its strong smell is very pervasive. It lingers in the mouth and body. Like asparagus, it contains certain amino acids that give a strong smell to one's urine, an effect that can be noticed up to two days after consumption. Like other beans, their complex carbohydrates can also cause strong-smelling flatulence.

Indonesia.

In Indonesia, "petai" is very popular in the highlands of Java and Sumatra, especially among Sundanese, Minangkabau and many other people in different cultures of the island. In Sundanese cuisine "petai" might be eaten raw with "sambal" as part of "lalab", fried or grilled. It also can be stir fried and mixed with "oncom". In Java and Sumatra, it also might be added to "sayur lodeh" or "sambal goreng ati petai" (fried diced beef or chicken liver in "sambal" and "petai"). "Nasi goreng kambing petai" is popular variant of "nasi goreng" (fried rice) with goat meat and petai. In Minangkabau cuisine it usually become part of "lado" (Minang sambal) for "ayam pop" (Padang style fried chicken).

India.

In Manipur, it is grown mainly on all the hilly districts especially Kuki inhabited areas, who called it "Jonglha", Hmar tribes call it "Zawngṭa" It is grown in the hill district of Hmârbiel and some other parts of Manipur valley. Varieties found here are somewhat harder than the counterparts of Thailand or Malaysia. The wild variety from the hills is more commonly sold in market. Some species of "Parkia" are grown in small scale by farmers in northeast India. In mainland India, it is grown as an ornamental plant, shade tree and border tree. This bean has become an important ingredient in many food items in Tripura too.  In Manipur, the seeds or the bean as a whole are eaten by preparing a local delicacy called "Hmarcha dêng", Eromba or Yongchaak singju (salad). Eromba is a very common cuisine in Manipur made with boiled potato, fermented fish, chili and other vegetables, in this case, Parkia. "Yongchaak singju" is another favourite side dish made with "Parkia" cut into small pieces and then mixed with red hot chili paste. Parkia is also used for making various other dishes with fish and vegetables.The Kuki Tribe,a tribe from North-East India, called it "Jonglha" and relished it with almost like a special vegetable. Rongmei Tribe of Manipur, Nagaland and Assam call it "Kampai" which is cooked with meat or prepared as salad, and sometimes seeds are eaten with "Chattni" made of dry fish. The Hmar tribe of Assam, Mizoram, Meghalaya, Manipur call it " Zawngṭa" (pronounced Zongtra) and mainly prepare it with chilli, Sodium Bi-carbonate, little amount of salt and a special fermented pork called "Saum"(sa means meat,um means fermented) and called it " Zawngṭa-râwt".  In Mizoram, the Mizo people are also very fond of it, and call it " Zawngṭah" and they use to prepare it with chili and a fermented pork called "Saum" which is the same as'sathu' of Manipur. In Manipur, Assam, Tripura, the (Tripura people call it "Wakerec mosedang") and Bangladesh Manipuris call it Yongchak or wakerec in the local manipuri dialect and consume it as a salad mixed with fermented fish or, the boiled or roasted seeds either alone or in a mash of boiled vegetables laced with fermented fish.

Malaysia & Singapore.

In Malaysia and Singapore, petai is also commonly served with sambal, or mixed with dried shrimp, chili peppers, red onions, belacan (prawn paste), soy sauce and prawn.

Thailand.

In Thailand it is called "sah-taw" (), as "mu phat sah-taw", stink bean with stir fried pork.

Parkia speciosa (the bitter bean, twisted cluster bean, or stink bean) is a plant of the genus "Parkia" in the family Fabaceae. It bears long, flat edible beans with bright green seeds the size and shape of plump almonds which have a rather peculiar smell, similar to, but stronger than that of the shiitake mushroom, due to sulfur-containing compounds also found in shiitake, truffles and cabbage.

臭豆(学名:')又名美丽球花豆、巴克豆,是一种属于豆科球花豆属的木本植物。豆荚长扁形,豆荚里面有亮绿色的种子,种子可以食用,豆子具有特殊的味道。


History.

Creation.

The domain name "bitcoin.org" was registered on 18 August 2008. On 31 October 2008, a link to a paper authored by Satoshi Nakamoto titled "Bitcoin: A Peer-to-Peer Electronic Cash System" was posted to a cryptography mailing list. Nakamoto implemented the bitcoin software as open-source code and released it in January 2009. Nakamoto's identity remains unknown.  On 3 January 2009, the bitcoin network was created when Nakamoto mined the first block of the chain, known as the "genesis block". Embedded in the coinbase of this block was the text "The Times 03/Jan/2009 Chancellor on brink of second bailout for banks". This note references a headline published by "The Times" and has been interpreted

2011–2012.

After early "proof-of-concept" transactions, the first major users of bitcoin were black markets, such as Silk Road. During its 30 months of existence, beginning in February 2011, Silk Road exclusively accepted bitcoins as payment, transacting 9.9 million in bitcoins, worth about $214 million.  In 2011, the price started at $0.30 per bitcoin, growing to $5.27 for the year. The price rose to $31.50 on 8 June. Within a month the

2013–2016.

In 2013, prices started at $13.30 rising to $770 by 1 January 2014.  In March 2013 the blockchain temporarily split into two independent chains with different rules due to a bug in version 0.8 of the bitcoin software. The two blockchains operated simultaneously for six hours, each with its own version of the transaction history from the moment of the split. Normal operation was restored when the majority of the network downgraded to version 0.7 of the bitcoin software, selecting the backward compatible version of the blockchain. As a result, this blockchain became the longest chain and could be accepted by all participants, regardless of their bitcoin software version. During the split, the Mt. Gox exchange briefly halted bitcoin deposits and the price dropped by 23% to $37 before recovering to previous level of approximately $48 in the following hours.  The US Financial Crimes Enforcement Network (FinCEN) established regulatory guidelines for "decentralized virtual currencies" such as bitcoin, classifying American bitcoin miners who sell their generated bitcoins as Money Service Businesses (MSBs), that are subject to registration or other legal obligations.  In April, exchanges BitInstant and Mt. Gox experienced processing delays due

2017–2019.

On 15 July 2017, the controversial Segregated Witness [SegWit] software upgrade was approved ("locked in"). Segwit was intended to support the Lightning Network as well as improve scalability. SegWit was subsequently activated on the network on 24 August 2017. The bitcoin price rose almost 50% in the week following SegWit's approval. On 21 July 2017, bitcoin was trading at $2,748, up 52% from 14 July 2017's $1,835. Supporters of large blocks who were dissatisfied with the activation of SegWit forked the software on 1 August 2017 to create Bitcoin Cash.  Prices started at $998 in 2017 and rose to $13,412.44 on 1 January 2018, after reaching its all-time high of $19,783.06 on 17 December 2017.  China banned trading in bitcoin, with first steps taken in September 2017, and a complete ban that started on 1 February 2018. Bitcoin prices then fell from $9,052 to $6,914 on

2020.

According to "CoinMetrics" and "Forbes", on 11 March 281,000 bitcoins were sold by owners who held them for only thirty days. This compared to 4,131 bitcoins that had laid dormant for a year or more indicating that the

Design.

Units and divisibility.

The unit of account of the bitcoin system is a "bitcoin". Ticker symbols used to represent bitcoin are BTC and XBT. Its Unicode character is ₿. Small amounts of bitcoin

Blockchain.

The bitcoin blockchain is a public ledger that records bitcoin transactions. It is implemented as a chain of "blocks", each block containing a hash of the previous block up to the genesis block of the chain. A network of communicating nodes running bitcoin software maintains the blockchain. Transactions of the form "payer X sends Y bitcoins to payee Z" are broadcast to this network using readily available software applications.  Network nodes can validate transactions, add them to their copy of

Transactions.

Transactions are defined using a Forth-like scripting language. Transactions consist of one or more "inputs" and one or more "outputs". When a user sends bitcoins, the user designates each address and the amount of bitcoin being sent to that address in an output. To prevent double spending, each input must refer to a previous unspent output in the blockchain. The use of multiple inputs corresponds to the use of multiple coins in a cash transaction. Since transactions can have multiple outputs, users can send bitcoins to multiple recipients in one transaction. As in a cash transaction, the sum of inputs (coins used to pay) can exceed the intended sum of payments. In such a case, an additional output is used, returning the change back to the payer. Any input "satoshis" not accounted for in the transaction outputs become the transaction fee.

Transaction fees.

Though transaction fees are optional, miners can choose which transactions to process and prioritize those that pay higher fees. Miners may choose transactions based on the fee paid relative to their storage size, not the absolute amount of money paid as a fee. These fees are generally measured in "satoshis per byte (sat/b)". The size of transactions is dependent on the number of inputs used to create the transaction, and the number of outputs.

Ownership.

In the blockchain, bitcoins are registered to bitcoin addresses. Creating a bitcoin address requires nothing more than picking a random valid private key and computing the corresponding bitcoin address. This computation can be done in a split second. But the reverse, computing the private key of a given bitcoin address, is practically unfeasible. Users can tell others or make public a bitcoin address without compromising its corresponding private key. Moreover, the number of valid private keys is so vast that it is extremely unlikely someone will compute a key-pair that is already in use and has funds. The vast number of valid private keys makes it unfeasible that brute force could be used to compromise a private key. To be able

Mining.

"Mining" is a record-keeping service done through the use of computer processing power. Miners keep the blockchain consistent, complete, and unalterable by repeatedly grouping newly broadcast transactions into a "block", which is then broadcast to the network and verified by recipient nodes. Each block contains a SHA-256 cryptographic hash of the previous block, thus linking it to the previous block and giving the blockchain its name.  To be accepted by the rest of the network, a new block must contain a "proof-of-work" (PoW). The system used is based on Adam Back's 1997 anti-spam scheme, Hashcash. The PoW requires miners to find a number called a "nonce", such that when the block content is hashed along with the nonce, the result is numerically smaller than the network's difficulty target. This proof is

Supply.

The successful miner finding the new block is allowed by the rest of the network to reward themselves with newly created bitcoins and transaction fees., the reward amounted to 6.25 newly created bitcoins per block added to the blockchain, plus any transaction fees from payments processed by the block. To claim the reward, a special transaction called a "coinbase" is included with the processed payments. All bitcoins in existence have been created

Pooled mining.

Computing power is often bundled together or "pooled" to reduce variance in miner income. Individual mining rigs often have to wait for long periods to confirm a block of transactions and receive payment. In a pool, all participating miners get paid every time a participating server solves a block. This payment depends on the amount of work an individual miner contributed to help find that block.

Wallets.

A "wallet" stores the information necessary to transact bitcoins. While wallets are often described as a place to hold or store bitcoins, due to the nature of the system, bitcoins are inseparable from the blockchain transaction ledger. A wallet is more correctly defined as something that "stores the digital credentials for your bitcoin holdings" and allows one to access (and spend) them. Bitcoin uses public-key cryptography, in which two cryptographic keys, one public and one private, are generated. At its most basic, a wallet is a collection of these keys.  There are several modes which wallets can operate in. They have an inverse relationship with regards to trustlessness and computational requirements.  Third-party internet services called "online wallets" offer similar functionality but may be easier to use. In this case, credentials to access funds are stored with the online wallet provider rather than on the user's hardware. As a result, the user must have complete trust in the online wallet provider. A malicious provider or a breach in server security may cause entrusted bitcoins to be stolen. An example of such a security breach occurred with Mt. Gox in 2011.

Physical wallets.

"Physical wallets" store the credentials necessary to spend bitcoins offline and can be as simple as a paper printout of the private key: a "paper wallet". A paper wallet is created with a keypair generated on a computer with no internet connection; the private key is written or printed onto the paper and then erased from the computer. The paper wallet can then be stored in a safe physical location for later retrieval. Bitcoins stored using a paper wallet are said to be in "cold storage".  Cameron and Tyler Winklevoss, the founders of the Gemini Trust Co. exchange, reported that they had cut their paper wallets into pieces and stored them in envelopes distributed to safe deposit boxes across the United States. Through this system, the theft of one envelope would neither allow the thief to steal any bitcoins nor deprive the rightful owners

Implementations.

The first wallet program, simply named "Bitcoin", and sometimes referred to as the "Satoshi client", was released in 2009 by Satoshi Nakamoto as open-source software. In version 0.5 the client moved from the wxWidgets user interface toolkit to Qt, and the whole bundle was referred to as "Bitcoin-Qt". After the release of version 0.9, the software bundle was renamed "Bitcoin Core" to distinguish itself from the underlying network.

Forks.

Bitcoin Core is, perhaps, the best known implementation or client. Alternative clients (forks of Bitcoin Core) exist, such as Bitcoin XT, Bitcoin Unlimited, and Parity Bitcoin.  On 1 August 2017, a hard fork of bitcoin was created, known as Bitcoin Cash. Bitcoin Cash has a larger block size limit and had an identical blockchain at the time of fork. On 24 October 2017 another hard fork, Bitcoin Gold, was created. Bitcoin Gold changes the proof-of-work algorithm used in mining, as the developers felt that mining had become too specialized.

Decentralization.

Bitcoin is decentralized:

Trend towards centralization.

Researchers have pointed out at a "trend towards centralization". Although bitcoin can be sent directly from user to user, in practice intermediaries are widely used. Bitcoin miners join large mining pools to minimize the variance of their income. Because transactions on the network are confirmed by miners, decentralization of the network requires that no single miner or mining pool obtains 51% of the hashing power, which would allow them to double-spend coins, prevent certain transactions from being verified and prevent other miners from earning income. just six mining pools controlled 75% of overall bitcoin hashing power. In 2014 mining pool Ghash.io obtained 51% hashing power which raised significant controversies about the safety of the network. The pool has voluntarily capped their hashing power at 39.99% and requested other pools to act responsibly for the benefit of the whole network. over 70% of the hashing power and 90% of transactions were operating from China.  According to researchers, other parts of the ecosystem are also "controlled by a small set of entities", notably the maintenance of the client software, online wallets and simplified payment verification (SPV) clients.

Privacy.

Bitcoin is pseudonymous, meaning that funds are not tied to real-world entities but rather bitcoin addresses. Owners of bitcoin addresses are not explicitly identified, but all transactions on the blockchain are public. In addition, transactions can be linked to individuals and companies through "idioms

Fungibility.

Wallets and similar software technically handle all bitcoins as equivalent, establishing the basic level of fungibility. Researchers have pointed out that the history of each bitcoin is registered and publicly

Scalability.

The blocks in the blockchain were originally limited to 32 megabytes in size. The block size limit of one megabyte was introduced by Satoshi Nakamoto in 2010. Eventually

Ideology.

Satoshi Nakamoto stated in his white paper that: "The root problem with conventional currencies is all the trust that's required to make it work. The central bank must be trusted not to debase the currency, but the history of fiat currencies is full of breaches of that trust."

Austrian economics.

According to the European Central Bank, the decentralization of money offered by bitcoin has its theoretical roots in the Austrian school of economics, especially

Anarchism and libertarianism.

According to "The New York Times", libertarians and anarchists were attracted to the idea. Early bitcoin supporter Roger Ver said: "At first, almost everyone who got involved did so for philosophical reasons. We saw bitcoin as a great idea, as a way to separate money from the state." "The Economist" describes bitcoin as "a techno-anarchist project to create an online version of cash, a way for people to transact without the possibility of interference from malicious

Economics.

Bitcoin is a digital asset designed to work in peer-to-peer transactions as a currency. Bitcoins have three qualities useful in a currency, according to "The Economist" in January 2015: they are "hard to earn, limited in supply and easy to verify." Per some researchers,, bitcoin functions more as a payment system than as a currency.  Economists define money as serving the following three purposes: a store of value, a medium of exchange, and a unit of account. According to "The Economist" in 2014, bitcoin functions best as a medium of exchange. However, this is debated, and a 2018 assessment by "The Economist" stated that cryptocurrencies met none of these three criteria. Yale economist Robert J. Shiller writes that bitcoin has potential as a unit of account for measuring the relative value of goods, as with Chile's Unidad de Fomento, but that "Bitcoin in its present form [...] doesn’t really solve any sensible economic problem".  According to research by Cambridge University, between 2.9 million and 5.8 million unique users used a cryptocurrency wallet in 2017, most of them for bitcoin. The number of users has grown significantly since 2013, when there were 300,000–1.3 million users.

Acceptance by merchants.

The overwhelming majority of bitcoin transactions take place on a cryptocurrency exchange, rather than being used in transactions with merchants. Delays processing payments through the blockchain of about ten minutes make bitcoin use very difficult in a retail setting. Prices are not usually quoted in units of bitcoin and many trades involve one, or sometimes two, conversions into conventional currencies. Merchants that do accept bitcoin payments may use payment service providers to perform the conversions.  In 2017 and 2018 bitcoin's acceptance among major

Financial institutions.

Bitcoins can be bought on digital currency exchanges.  Per researchers, "there is little sign of bitcoin use" in international remittances despite high fees charged by banks and Western Union who compete in this market. The South China Morning Post, however, mentions the use of bitcoin by Hong Kong workers to transfer money home.  In 2014, the National Australia Bank closed accounts of businesses with ties to

As an investment.

The Winklevoss twins have purchased bitcoin. In 2013, "The Washington Post" reported a claim that they owned 1% of all the bitcoins in existence at the time.  Other methods of investment are bitcoin funds. The first regulated bitcoin fund was established in Jersey in July 2014 and approved

Venture capital.

Peter Thiel's Founders Fund invested million in BitPay. In 2012, an incubator for bitcoin-focused start-ups was founded by Adam Draper, with financing help from his father, venture capitalist Tim Draper, one of the largest bitcoin holders after winning an

Price and volatility.

The price of bitcoins has gone through cycles of appreciation and depreciation referred to by some as bubbles and busts. In 2011, the value of one bitcoin rapidly rose from about US$0.30 to US$32 before returning to US$2. In the latter half of 2012 and during the 2012–13 Cypriot financial crisis, the bitcoin price began to

Legal status, tax and regulation.

Because of bitcoin's decentralized nature and its trading on online exchanges located in many countries, regulation of bitcoin has been difficult. However, the use of bitcoin can be criminalized, and shutting down exchanges and the peer-to-peer economy in a given country would constitute a de facto ban. The legal status of bitcoin varies substantially from country to country and is still undefined or changing in many of them. Regulations and bans that apply to bitcoin probably extend to similar cryptocurrency systems.  According to the Library of Congress, an "absolute ban" on trading or using cryptocurrencies applies in nine countries: Algeria, Bolivia, Egypt, Iraq, Morocco, Nepal, Pakistan, Vietnam, and the United Arab Emirates. An "implicit ban" applies in another 15 countries, which include Bahrain, Bangladesh, China, Colombia, the Dominican Republic, Indonesia, Iran, Kuwait, Lesotho, Lithuania, Macau, Oman, Qatar, Saudi Arabia and Taiwan.

Regulatory warnings.

The U.S. Commodity Futures Trading Commission has issued four "Customer Advisories" for bitcoin and related investments. A July 2018 warning emphasized that trading in any cryptocurrency is often speculative, and there is a risk of theft from hacking, and fraud. In May 2014 the U.S. Securities and Exchange Commission warned that investments

Price manipulation investigation.

An official investigation into bitcoin traders was reported in May 2018. The U.S. Justice Department launched an investigation into possible price manipulation, including the techniques of spoofing and wash trades.  The U.S. federal investigation was prompted by concerns of possible manipulation during futures settlement dates. The final settlement price of CME bitcoin futures is determined by prices on four exchanges, Bitstamp, Coinbase, itBit and Kraken. Following the first delivery date in January 2018, the CME requested extensive detailed trading information but several of the exchanges refused to provide it and later provided only limited data. The Commodity Futures Trading Commission then subpoenaed the data from the exchanges.

Criticism.

The Bank for International Settlements summarized several criticisms of bitcoin in Chapter V of their 2018 annual report. The criticisms include the lack of stability in bitcoin's price, the high energy consumption, high and variable transactions costs, the poor security and fraud at cryptocurrency exchanges, vulnerability to debasement (from forking), and the influence of miners.  "The Economist" describes these criticisms as unfair, predominantly because the shady image may compel users to overlook the capabilities of the blockchain technology, but also due to the fact that the volatility of bitcoin is changing in time.

As a speculative bubble.

Bitcoin, along with other cryptocurrencies, has been described as an economic bubble by at least eight Nobel Memorial Prize in Economic Sciences laureates, including Robert Shiller, Joseph Stiglitz, and Richard Thaler. Noted Keynesian economist Paul Krugman has described bitcoin as "a bubble wrapped in techno-mysticism inside a

Energy consumption.

Bitcoin has been criticized for the amount of electricity consumed by mining., "The Economist" estimated that even if all miners used modern facilities, the combined electricity consumption would be 166.7 megawatts (1.46 terawatt-hours per year). At the end of 2017, the global bitcoin mining activity was estimated to consume between one and four gigawatts of electricity. By 2018, bitcoin was estimated by "Joule" to use 2.55 GW, while "Environmental Science & Technology" estimated bitcoin to consume 31.29 TWh for the year (this corresponds to the use of 3.572 GW). In July 2019 BBC reported bitcoin consumes

Carbon footprint.

Concerns about bitcoin's environmental impact relate bitcoin's energy consumption to carbon emissions. The difficulty of translating the energy consumption into carbon emissions lies in the decentralized nature of bitcoin impeding the localization of miners to examine the electricity mix used. The results of recent studies analyzing bitcoin's carbon footprint vary. A study published in "Nature Climate Change" in 2018 claims that bitcoin "could alone produce enough emissions to push warming above 2 °C within less than

Ponzi scheme and pyramid scheme concerns.

Journalists, economists, investors, and the central bank of Estonia have voiced concerns that bitcoin is a Ponzi scheme. In April 2013, Eric Posner, a law professor at the University of Chicago, stated that "a real Ponzi scheme takes fraud; bitcoin, by contrast, seems

Security issues.

Bitcoin is vulnerable to theft through phishing, scamming,

Use in illegal transactions.

The use of bitcoin by criminals has attracted the attention of financial regulators, legislative bodies, law enforcement, and the media. Bitcoin gained early notoriety for its use on the Silk Road. The U.S. Senate held a hearing on virtual currencies in November 2013. The U.S. government claimed that bitcoin was used to facilitate payments related to Russian interference in the 2016 United States elections.  Several news outlets have asserted that the popularity of bitcoins

Other critical opinions.

François R. Velde, Senior Economist at the Chicago Fed, described it as "an elegant solution to the problem of creating a digital currency".  David Andolfatto, Vice President at the Federal Reserve Bank of

In popular culture.

Literature.

In Charles Stross' 2013 science fiction novel, "Neptune's Brood", the universal interstellar payment system is known as "bitcoin" and operates using cryptography. Stross later blogged that the reference

Film.

The 2014 documentary "The Rise and Rise of Bitcoin" portrays the diversity of motives behind the use of bitcoin by interviewing people

Academia.

In September 2015, the establishment of the peer-reviewed academic journal "Ledger" () was announced. It covers studies of cryptocurrencies and related technologies, and is published by the

Bitcoin (₿) is a cryptocurrency. It is a decentralized digital currency without a central bank or single administrator that can be sent from user to user on the peer-to-peer bitcoin network without the need for intermediaries.

比特币(英语:Bitcoin,缩写:BTC 或 XBT)是一种基于去中心化,采用点对点网络与共识主动性,开放源代码,以区块链作为底层技术的加密货币,比特币由中本聪(网名)(Satoshi Nakamoto)于2008年10月31日发表论文,2009年1月3日,创世区块诞生。在某些国家、央行、政府机关则将比特币视为虚拟商品,而不认为是货币。


History.

The Accord lists a series of agreements between the Federation of Malaya, the Republic of Indonesia, and the Republic of the Philippines, and a joint statement by all three parties.  Effective 24 September 1963, the Philippine Embassy in Kuala Lumpur closed down upon the Malayan government’s orders, following a failure to reach a satisfactory settlement of the Philippines’ claim to eastern North Borneo, and the deferment of recognition of the successor state, Malaysia. Diplomatic and consular relations between the two countries remained suspended until May 1964.  On 7 February 1966, relations between the Philippines and Malaysia became calmer and had stabilised, during which time an exchange of notes constituting an agreement relating to the implementation of the Manila Accord of 31 July 1963 (signed by Philippines and Malaysia at Manila and Kuala Lumpur constituting that both Governments had agreed to abide by the "Manila Accord of 31 July 1963") and the accompanying "Joint Statement", called for the peaceful settlement of the Philippine claim to eastern North Borneo. The agreements also recognized the need for the parties to come together, as soon as possible, for the purpose of clarifying the claim and discussing the means of settling it to the satisfaction of both parties in consonance with the "Manila Accord" and the "Joint Statement".  The "Manila Accord" with the "Joint Statement", and the "Agreement relating to the implementation of the Manila Accord of 31 July 1963" were registered and published after their entry into force had been transmitted to the Secretary-General of the United Nations by the Government of the Republic of the Philippines on 30 December 1965 and 24 October 1967, respectively. Compliance with Article 80 of the Vienna Convention on the Law of Treaties (1969) would lead envisaged jurisdiction of the International Court of Justice for decision unless the parties by common consent could agree to submit the dispute to arbitration.

The Manila Accord was signed on 31 July 1963 by the Federation of Malaya, the Republic of Indonesia and the Republic of the Philippines, after a meeting from 7 to 11 June 1963 in Manila.

马尼拉协定(英语:Manila Accord)在经过马来亚联合邦、菲律宾共和国和印度尼西亚共和国于1963年6月11日在马尼拉共同签署。在此之前三国于马尼拉一起举行了由1963年6月7日至10日长达3日的会议。


Geography.

Petrogradsky Island lies between the Neva River and its Bolshaya Nevka branch. It is separated from Aptekarsky Island on the north by the Karpovka River, from Krestovsky Island on the west by the Malaya Nevka, from Petrovsky Island on the south by the Zhdanovka River, and from Zayachy Island on the southeast by the Kronverksky Strait. It is linked to the central district by the Troitsky Bridge, to Vasilievsky Island by the Birzhevoy "(Exchange)" Bridge and Tuchkov Bridge), to Petrovsky Island by the Maly Petrovsky Bridge, to Krestovsky Island by the Lazarevsky Bolshoy Krestovsky Bridges, and to the Vyborgskaya Side via the Sampsonievsky and Grenadersky Bridges.

History.

Finnish and Swedish farms added to a large Russian settlement, continuing to develop the island in the 17th century. In 1703 Tsar Peter the Great of Russia laid the foundation of the Peter and Paul Fortress on nearby Zayachy Island. During this time, he resided near the present-day site of Troitsky Square near the southeastern tip of island, known at that time as Gorodskoy Island. It was renamed Peterburgsky Island or Sankt-Peterburgsky Island after Peter's death in 1725. The administrative center of Saint Petersburg moved to Vasilievsky Island in the 1720s, and in the 1730s, stone buildings north of the Kronverk were banned. As a result, the island became more residential and suburban. One of the earliest main avenues, dating from the 1730s, is the Bolshoy Prospekt, crossing the island from the northeast to the Tuchkov Bridge in the southwest. The Yamburgsky, Koporsky, St. Petersburg, and Belozersky regiments had their quarters on the island at that time, and the new road served to connect them all. Horsecars first ran in the 1860s, followed by trams in 1908 and trolleybuses in 1948. The other main avenue, the Kamennoostrovsky Prospekt, intersects the Bolshoy Prospekt in the north at Leo Tolstoy Square and runs southeast to the present-day Troitsky Bridge. The avenue was constructed in the 18th century, leading from the Kronverk esplanade to Kamenny Island. In the 1820s there was a high road with special paving. In the 1870s, horsecars started operating along the avenue, and in 1909, an electric tramway was introduced. In 1903 the avenue extended as far as Troitskaya Square.  When Saint Petersburg was renamed Petrograd in 1914, the island received its present name, Petrogradsky Island.

Places of interest.

Petrogradsky Island is the home of several noted universities, science and research institutes. The Saint Petersburg Pavlov State Medical University, located at 6/8 Leo Tolstoy Street, was founded in 1897 as the first Russian medical institute for women.  The Saint Petersburg State University of Information Technologies, Mechanics and Optics is one of Russia's leading technical universities. The A. F. Mozhaisky Military Space Engineering Academy (13 Zhdanovskaya street) is a polytechnical military educational institution and space research center.  Of historical interest is the Cruiser Aurora, the oldest commissioned ship in the Russian Navy and a symbol of the October Revolution of 1917. A museum since 1956, it is anchored in the Bolshaya Nevka, near the Sampsonievsky bridge. Just north of the Kronwerk, in the former "Aquarium Gardens", the first motion picture was shown in Russia in 1896, at what is now Lenfilm Studios The island also houses the Baltic House Festival Theatre, the Yubileyny Sports Palace, the Saint Petersburg Planetarium and the Leningrad Zoo.

Petrogradsky Island (Russian: Петроградский остров) is the third largest island in the Neva River delta in Saint Petersburg, Russia. Along with Zayachy Island, Aptekarsky Island, and Petrovsky Island, it constitutes the Petrogradskaya Side (Russian: Петроградская сторона). It is the administrative center of the Petrogradsky District and hosts a number of universities and research centers, as well as cultural, historical, and recreational facilities.

彼得格勒岛()位于涅瓦河入海口涅瓦河三角洲,被涅瓦河、日当诺夫卡、小小涅瓦河、卡尔波夫卡、大小涅瓦河和克容维尔科斯基海峡环绕。是圣彼得堡市彼得格勒区最大的岛,也是涅瓦河三角洲的最大岛之一