5930637
Parallelization of IBM mambo system simulator in functional modes
Mambo [4] is IBM's full-system simulator which models PowerPC systems, and provides a complete set of simulation tools to help IBM and its partners in pre-hardware development and performance evaluation for future systems. Currently Mambo simulates target systems on a single host thread. When the number of cores increases in a target system, Mambo's simulation performance for each core goes down. As the so-called "multi-core era" approaches, both target and host systems will have more and more cores. It is very important for Mambo to efficiently simulate a multi-core target system on a multi-core host system. Parallelization is a natural method to speed up Mambo under this situation.
 Parallel Mambo (P-Mambo) is a multi-threaded implementation of Mambo. Mambo's simulation engine is implemented as a user-level thread-scheduler. We propose a multi-scheduler method to adapt Mambo's simulation engine to multi-threaded execution. Based on this method a core-based module partition is proposed to achieve both high inter-scheduler parallelism and low inter-scheduler dependency. Protection of shared resources is crucial to both correctness and performance of P-Mambo. Since there are two tiers of threads in P-Mambo, protecting shared resources by only OS-level locks possibly introduces deadlocks due to user-level context switch. We propose a new lock mechanism to handle this problem. Since Mambo is an on-going project with many modules currently under development, co-existence with new modules is also important to P-Mambo. We propose a global-lock-based method to guarantee compatibility of P-Mambo with future Mambo modules.
 We have implemented the first version of P-Mambo in functional modes. The performance of P-Mambo has been evaluated on the OpenMP implementation of NAS Parallel Benchmark (NPB) 3.2 [12]. Preliminary experimental results show that P-Mambo achieves an average speedup of 3.4 on a 4-core host machine.
2930673
Adaptive Security Dialogs for Improved Security Behavior of Users
Despite the increasing awareness of the importance of security for daily computer users, we see that many users still fail to behave securely when confronted with a security-related decision. In this paper, we introduce a new approach to security-related dialogs called Adaptive Security Dialogs (ASD). This approach is a combination of a new architecture and a new way of interacting with users to provide them with appropriate and effective security dialogs. ASD realizes this goal by matching the complexity and intrusiveness of security-related dialogs to the risk associated with the decision the user is making. This results in an architecture in which users can focus on their tasks, get (immediate) feedback on their decisions, and interact with dialogs with an appropriate complexity and appearance for the decision's associated risk. This paper makes the following three contributions. First, we introduce a general architecture for handling security-related decisions. Second, through an empirical user study using a web-based e-mail client, we show significant improvement in the care exercised by our participants without sacrificing usability. Third, we describe how the different pieces of existing research fit into the bigger picture of improving users' behavior.
16356479
A multi-agent simulation for social agents
Agent-based modeling of human social behavior is an increasingly important research area. Many fully functional multi-agent systems have been developed and have been put to use over the years. But efficient scalable and robust social systems are difficult to engineer, both from the modeling perspective and the implementation perspective. There exist three important difficulties. First, the system needs to have an adaptable agent framework that can successfully make intuitive and deliberative decisions much like a real social participant would. Secondly, the system must have a robust architecture that not only ensures its functioning no matter the simulation, but also provides an easily understood interface that researchers can interact with while running their simulations. Finally, the system must be effectively distributed to handle the necessary number of agents that social research requires to obtain meaningful results. This paper presents our work on creating a multi-agent simulation for social agents that would overcome these three difficulties. Lastly, we present a simulation to test the system and provide the results of that simulation.
119556859
Eventual practical stability of impulsive differential equations with time delay in terms of two measurements
In this paper we introduce a new stability--eventual practical stability for impulsive differential equations with time delay. By using Lyapunov functions and comparison principle, we will get some criteria of eventual practical stability, eventual practical quasistability and strong eventual practical stability for impulsive differential equations with time delay in terms of two measurements.
35510017
A Link-Based Rank of Postings in Newsgroup
Discussion systems such as Usenet, BBS, Forum are important resources for information sharing, view exchanging, problem solving and product feedback, etc. on Internet. The postings in newsgroups on Usenet represents the judgments and choices of participators. The structure of postings could provide helpful information for the users. In this paper, we present a method called PostRank to rank the postings based on the structure of newsgroup. Its results correspond to the eigenvectors of the transition probability matrix and the stationary vectors of the Markov chains. It could provide useful global information for the newsgroup and it can be used to help the users access information in it more effectively and efficiently. This method can be also applied on other discussion systems. Some experimental results and discussions on real data sets collected by us are also provided.
6483143
Using Proximity in Query Focused Multi-document Extractive Summarization
The query focused multi-document summarization tasks usually tend to answer the queries in the summary. In this paper, we suggest introducing an effective feature which can represent the relation of key terms in the query. Here, we adopt the feature of term proximity commonly used in the field of information retrieval, which has improved the retrieval performance according to the relative position of terms. To resolve the problem of data sparseness and to represent the proximity in the semantic level, concept expansion is conducted based on WordNet. By leveraging the term importance, the proximity feature is further improved and weighted according to the inverse term frequency of terms. The experimental results show that our proposed feature can contribute to improving the summarization performance.
7672026
A power and temperature aware DRAM architecture
Technological advances enable modern processors to utilize increasingly larger DRAMs with rising access frequencies. This is leading to high power consumption and operating temperature in DRAM chips. As a result, temperature management has become a real and pressing issue in high performance DRAM systems. Traditional low power techniques are not suitable for high performance DRAM systems with high bandwidth. In this paper, we propose and evaluate a customized DRAM low power technique based on page hit aware write buffer (PHA-WB). Our proposed approach reduces DRAM system power consumption and temperature without any performance penalty. Our experiments show that a system with a 64-entry PHA-WB could reduce the total DRAM power consumption by up to 22.0% (9.6% on average). The peak and average temperature reductions are 6.1degC and 2.1degC, respectively.