40653800
Coordination Research on Key Parameters in Generation Competition Based on Dynamic Simulation
Power generation adequacy is critical for the reliability of electricity supply service, and therefore its investment draws much attention. This paper builds a dynamic simulation model to solve the setting of two key parameters, the energy price cap and the capacity price in the generation market, and applies this model to various cases to analyze the generation capacity development. Based on the simulation results, this paper analyzes the sensitivity of generation capacity to the key parameters. Furthermore, this paper proposes an evaluation index system for the simulation model, and discusses the correlation between the two key parameters, from the views of reliability and economy. The research shows that there might be potential unmarked misunderstandings in the setting of key parameters, and suggests that under a certain electricity bill for customers, parameter combination of low energy price cap and high capacity price should be made, in order to curb the fluctuation of generation capacity and maintain the system reliability.
25711075
Externality Identification and Quantification of Transmission Construction Projects
This paper provides the evaluation method and model of the externality of the transmission projects, and identifies both negative and positive externalities, as well as makes quantitative and qualitative analysis of externality. In order to quantify the impact of transmission construction projects on the power flow distribution, power supply and demand, as well as the power price of the neighboring power grid, this paper operates the optimal power flow calculation on the Matlab platform through using the IEEE 30-Node Prototype System, and figures out the construction project's influence on the economic benefits of different power market participants. Based on the existing environmental evaluation study, this paper analyzes how the transmission construction project affects the natural resource and the environment and the daily life of the inhabitants. Taking into account the externality and quantifying the externality when evaluating the investment project can help the government and the investors to make the investment decision which is beneficial to the whole society.
42507364
Dynamic Equivalents of Power System Based on Extended Two Particle Swarm Optimization
A novel methodology based on phaser measurement units (PMUs) for power system dynamic equivalents is presented. In this methodology the external system is reduced dynamically using the important quantities obtained by PMUs. An extended two particle swarm optimization (PSO) algorithm with the mutation operator is proposed to identify the parameters of the equivalent system. The proposed method is demonstrated and compared with the original system using the 10 machines 39 buses New England test system. The comparison shows that the proposed method can preserve the dynamic properties of the original system and has great value in engineering application.
11814255
Core role-based access control: efficient implementations by transformations
This paper describes a transformational method applied to the core component of role-based access control (RBAC), to derive efficient implementations from a specification based on the ANSI standard for RBAC. The method is based on the idea of incrementally maintaining the result of expensive set operations, where a new method is described and used for systematically deriving incrementalization rules. We calculate precise complexities for three variants of efficient implementations as well as for a straightforward implementation based on the specification. We describe successful prototypes and experiments for the efficient implementations and for automatically generating efficient implementations from straightforward implementations.
13273680
Modular verification of dynamically adaptive systems
Cyber-physical systems increasingly rely on dynamically adaptive programs to respond to changes in their physical environment; examples include ecosystem monitoring and disaster relief systems. These systems are considered high-assurance since errors during execution could result in injury, loss of life, environmental impact, and/or financial loss. In order to facilitate the development and verification of dynamically adaptive systems, we separate functional concerns from adaptive concerns. Specifically, we model a dynamically adaptive program as a collection of (non-adaptive) steady-state programs and a set of adaptations that realize transitions among steady state programs in response to environmental changes. We use Linear Temporal Logic (LTL) to specify properties of the non-adaptive portions of the system, and we use A-LTL (an adapt-operator extension toLTL) to concisely specify properties that hold during the adaptation process. Model checking offers an attractive approach to automatically analyzing models for adherence to formal properties and thus providing assurance. However, currently, model checkers are unable to verify properties specified using A-LTL. Moreover, as the number of steady-state programs and adaptations increase, the verification costs (in terms of space and time) potentially become unwieldy. To address these issues, we propose a modular model checking approach to verifying that a formal model of an adaptive program satisfies its requirements specified in LTL and A-LTL, respectively.
606471
A dynamic scalable service model for SIP-based video conference
As an extensible signaling protocol, SIP (session initiation protocol) can be applied in developing video conference system. Traditionally, for SIP-based centralized video conference system, conferencing scale is limited by both the capability of conference server and the availability of bandwidth. The paper focuses on how to keep conferencing when the number of conference users increases. Based on the study of the SIP protocol, we analyze the drawback of the existing video conference model, and propose a dynamic scalable service model for SIP-based video conference. By this model, the extra service requests can be transferred and served in the cooperated conference servers. The paper presents the conferencing control policy of the model in detail. We developed a prototype of video conference system based on the above model. Experimental results show this service model works well.
8160654
Approximate treatment for calculation of the rate-distortion slope in EBCOT
Some novel approaches are presented aiming at reducing computation and memory for the EBCOT algorithm in JPEG2000. In the current structure of EBCOT, the algorithm for calculating the distortion reduction is still too complex for hardware-oriented design, and the memory space needed for the storage of large amounts of rate-distortion slopes is often unaffordable. In this paper, we propose a set of simplification schemes based on some approximate treatments by means of quantization median substitution and logarithm expression. These approaches can facilitate calculation of the rate-distortion slopes and reduce the memory by 50% (only 8 bits for each slope). Experimental results show that the quality of decoded images has only slightly decreased, which is negligible for most of the applications.