5737792
Generators Bidding Behavior in the NYISO Day-Ahead Wholesale Electricity Market
Statistical and econometric modeling is used to analyze the dynamics of generators' bidding behavior and resulting market prices in the NYISO day-ahead market during the summer of 2001 at three levels. First, at the generator level, generators' offered capacity is modeled by a two-stage sample selection process. The grouping choices of generators are estimated in the first stage. In the second stage, generators' offered capacity is estimated conditional on their grouping choices. Second, at the group level, we estimate the offer curves of each group. Third, at the total supply level, the aggregate supply curve is simulated by aggregating the offer curves of bidding groups. The estimated market prices based on the simulated supply curve can replicate most volatility of actual market prices. We find that demand conditions affect generators' bidding behavior and thus market prices significantly by applying our model under different demand assumptions
5773205
Auction-Based Pricing Model for Web Service Providers
Applying auctions to Web services selection and invocation calls for examination due to the unique features of Web services, such as interoperable machine-to machine interactions and re-enterable bargaining services. In this paper, we propose a formal model for Web services-based auctions. Examining a one sided sealed auction type, we prove mathematically that service requestorsâ€™ risk preferences could lead to different pricing strategies for service providers towards higher profit. We argue that Service Level Agreement (SLA) documents can be used to analyze service requestorsâ€™ preferences. On top of WS Agreement, we propose a basic service requestor risk preference elicitation algorithm, as well as a historical data-based service requestor risk preference prediction model. Guidelines are provided to iteratively approach the learning rate of the proposed risk preference prediction model. The methods and techniques presented in this paper can be reused to investigate and examine more facades of services-oriented auctions towards establishing a new research realm on comprehensive services-oriented auctions.
11164895
Primary-consistent soft-decision color demosaicking for digital cameras (patent pending)
Color mosaic sampling schemes are widely used in digital cameras. Given the resolution of CCD sensor arrays, the image quality of digital cameras using mosaic sampling largely depends on the performance of the color demosaicking process. A common problem with existing color demosaicking algorithms is an inconsistency of sample interpolations in different primary color channels, which is the cause of the most objectionable color artifacts. To cure the problem, we propose a new primary-consistent soft-decision framework (PCSD) of color demosaicking. In the PCSD framework, we make multiple estimates of a missing color sample under different hypotheses on edge or texture directions. The estimates are made via a primary consistent interpolation, meaning that all three primary components of a color are interpolated in the same direction. The final estimate of a color sample is obtained by testing different interpolation hypotheses in the reconstructed full-resolution color image and selecting the best via an optimal statistical decision or inference process. A concrete color demosaicking method of the PCSD framework is presented. This new method eliminates certain types of color artifacts of existing color demosaicking methods. Extensive experimental results demonstrate that the PCSD approach can significantly improve the image quality of digital cameras in both subjective and objective measures. In some instances, our gain over the competing methods can be as much as 7dB.
598542
XSEED: Accurate and Fast Cardinality Estimation for XPath Queries
We propose XSEED, a synopsis of path queries for cardinality estimation that is accurate, robust, efficient, and adaptive to memory budgets. XSEED starts from a very small kernel, and then incrementally updates information of the synopsis. With such an incremental construction, a synopsis structure can be dynamically configured to accommodate different memory budgets. Cardinality estimation based on XSEED can be performed very efficiently and accurately. Extensive experiments on both synthetic and real data sets show that even with less memory, XSEED could achieve accuracy that is an order of magnitude better than that of other synopsis structures. The cardinality estimation time is under 2% of the actual querying time for a wide range of queries in all test cases.
445053
Prediction of Helix, Strand Segments from Primary Protein Sequences by a Set of Neural Networks
In prediction of secondary structure of proteins there are always some suspected segments. These suspected segments confuse people and lower the accuracy of prediction methods. To deal with this problem, a set of neural networks (NNs) are built based on helix, strand and coil segments selected from PDB. The test performance of these NNs on training data is perfect without surprise. However the prediction on test data is not good enough because the training data are lake of great representativeness. The results support the fact that closer neighbor vectors have the similar outputs of NNs. One can improve representativeness of training data without enlarging data scale as long as select less data from dense region and more from sparse region on condition that distribution of sample data has been known.
15419167
VISSIM-Based Simulation of the Left-Turn Waiting Zone at Signalized Intersection
In order to simulate traffic movements of the left-turn waiting zone (LWZ) at signalized intersection to quantitatively evaluate the operational performances after the implementation of the LWZ, following the introduction of the concept of the LWZ, its application environment were recommended, the modeling method of the LWZ was established, and the simulation evaluation indexes were introduced. Based on the data investigation, the simulation model was applied to a typical signalized intersection with the LWZ by micro-simulation software VISSIM to evaluate the efficiency of the traffic operation. It is found that compared with the layout of lacking LWZ, the left-turn traffic capacity at signalized intersection increased by 5.9, 4.3 and 6.7 percent in three different periods of traffic levels respectively after using the LWZ. The result shows that optimizing the layout of the intersection by using the LWZ can improve the operation efficiency without affecting the traffic safety.
39485215
Security issues in an EDI environment
EDI (Electronic Data Interchange) means electronic transmission, processing, and storage of commercial, business, or trade related documents. The paper surveys the security threats posed to an EDI system, and outlines the techniques and services used to counter these threats. Most importantly, the paper has gone into great depth to address an EDI specific security requirement-non repudiation of receipt. The current related work done to support this service is first discussed, and then a new and simple, but effective protocol to achieve non repudiation of receipt on a distributed and heterogeneous system platform is proposed.