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Abstract: This paper presents practical performance study of one axis mechanical tracking of PV grid connected system, which is designed, studied, and analyzed comparing with a fixed PV system at HIAST with capacity of 100 watts with tilt angle 35 degrees. This paper presents and compares the capital costs of tracking and fixed systems and the energy injected into the grid. [Copyright &y& Elsevier]

Abstract: The European Union has set a goal that the energy use in the built environment shall be reduced by 41% to the year 2050 compared to 2005-2006. This could introduce new opportunities for solar thermal systems in cold countries. In such countries, like Sweden and Canada, the economy in solar thermal collector installation projects is often spoiled by the fact that most of heating energy demand of the building occurs during periods when the available solar energy is low. The present paper investigates the performance of solar thermal systems subjected to different quota between space heating and domestic hot water demand (DHW). This study investigates the performance of a solar thermal system integrated to four different buildings with varying heating loads in two different locations, Sweden and Canada. Models of single family houses are created which are able to simulate the total heating demand with different heating demand profiles but the same DHW demand. Simulations are performed in TRNSYS, an advanced tool used to simulate transient systems. Results indicate that solar combisystems tend to generate more useful energy and therefore be more cost effective when installed in buildings with higher heating demands. [Copyright &y& Elsevier]

Abstract: In this paper the comparison between the performance of a cross flow heat exchanger in wet and dry operation for air handling process has been investigated. In addition, a case study of application of the component to perform indirect evaporative cooling in a AHU was studied with the software TRNSYS.Using experimental data and an appropriate analytical method, energy saving performances of the system has been evaluated through the entire cooling season for a typical Mediterranean site. Results show that high energy saving potential can be obtained if the component is operated in wet operation in term of reduction of electricity consumption. [Copyright &y& Elsevier]

Abstract: Large solar thermal systems (LSTS) are a promising market segment for solar energy. However, the realization of LSTS is more challenging compared to smaller plants, in both technical and economical terms. Permanent monitoring, data evaluation and fault detection during the operation of LSTS has shown by Fink et al. [3] and Peuser et al. [13] to be crucial for ensuring optimal performance. The only cost-effective way for permanent surveillance of LSTS operation is to make use of a computer-aided tool that performs as many steps as possible in an automated mode. The R&D project ‘IP-Solar’ developed the scientific basis and the technical fundamentals for such a system. This paper presents the current state of development emphasizing the methodology of the operation diagnostics. In particular, the algorithm-based approach, its implementation and testing are described in detail. [Copyright &y& Elsevier]

Abstract: Since its discovery, electrical energy represents one of the most decisive fields in any technology. In this paper, a comparative study between fixed hysteresis band current control (HBCC) and adaptive hysteresis band current control techniques in speed drive system is presented. These techniques control the variation of output voltage of the three phase rectifier. The theory and analysis of both the conventional fixed-HBCC and the adaptive HBCC which are the control techniques that operate at any condition with variable and constant switching frequency, are respectively developed. At the end, the performance of such control technique has been observed and discussed thanks to a simulation study carried with Matlab Simulink environnement. [Copyright &y& Elsevier]

Abstract: There are many methods available for Load frequency control in an interconnected power system. This paper deals with tuning of PID controller for Load frequency control. A two area thermal power system is considered for study. Both the areas are equipped with PID controller. Parameters of these PID controllers are obtained using Particle Swarm Optimization. A comparative study on tuned values has been presented to verify effectiveness. Ziegler-Nichols method is used for tuning of parameters for comparative study. The simulation results demonstrate the effectiveness of the designed system in terms of reduced settling time and oscillations. MATLAB/SIMULINK was used as simulation tool. [Copyright &y& Elsevier]

Abstract: Up to now, a number of linear discriminant analysis (LDA) methods have been developed. Though all these methods have a goal of maximizing the between-class distance and of minimizing the within-class distance, they are formally different and seem to have different performance. This paper aims at revealing the similarity and difference between different matrix-based LDA methods, which is helpful for people to better understand these methods. We first use a formally united framework to present the LDA methodology including different LDA methods and then perform comparison experiments of two LDA methods. [Copyright &y& Elsevier]

Abstract: Security issues of space information network can’t be ignored, and it is necessary to construct proper models when researching on security protocols of space information network. This paper studies three modeling methods of security protocol based on OPNET, including process model, custom multi-tier application and ACE whiteboard. All of these three methods are discussed in details by introducing the modeling procedure of Diffie-Hellman key exchange protocol. Performance of these three methods are analyzed and compared from the aspects of modeling capability, protocol layer and realizing complexities. One of the methods is validated in the simulation platform of space information network. [Copyright &y& Elsevier]

Abstract: Motion estimation based on block matching plays a very important role in video coding. In this paper, a fast motion estimation algorithm was proposed—three-step diamond search (TSDS), which is an improved version of the diamond search algorithm. This algorithm can be used for the new video coding standard H.264/AVC. Compared with diamond search (DS), the TSDS algorithm achieves the performance but the searching points are less 20% on average. Experimental results show that the proposed algorithm greatly outperforms four-step search and DS in the number of searching points. [Copyright &y& Elsevier]

Abstract: Cooperative spectrum sensing in cognitive radio networks can significantly improve the sensing performance. But it is vulnerable to attack in which malicious nodes report false detection results. In this paper, we introduce a trust mechanism into cooperative spectrum sensing and propose a Trust Mechanism-based Secure Cooperative Spectrum Sensing scheme (TM-SCSS) in which fuse center allocates trust value to each node and updates the trust value according to the consistency detection of local sensing result and global decision. Cooperating nodes are categorized into malicious node, pending node and trusted node according to its trust value and different fusing schemes are adopted correspondingly to utilize local sensing information synthetically and improve the security of cooperative sensing. At the same time, a second opportunity to attend decision-making is provided for malicious nodes to improve impartiality of cooperation. Simulations show that compared with the existing methods, the proposed scheme has better attack-proof characteristic and can operate reliably for long time when there are about 12% malicious nodes in the networks. [Copyright &y& Elsevier]

Abstract: In practical systems, Network-on-Chip (NoC) commonly employs irregular mesh topology because of variations in module sizes and shapes. In this paper, a solution to irregular 2-D mesh NoC, combining router table and fixed routing algorithm, is presented. Simulation indicates that the proposed irregular NoC demonstrates normally lower network performance compared to regular NoC with fixed routers, but reduces the router table cost to NoC with full router tables, e.g. by 51.2% for 4×4 2-D mesh topology. [Copyright &y& Elsevier]

Abstract: The jamming with high power is usually used to block the uplink channel of communication satellite, as a common method of interfering satellite. It was called High Power Blocking Jamming. This kind of jamming is very harmful to communication satellite, which could severely degrade the working performance. It is very difficult to remove such jamming because it has very high power. Nulling Antenna technology is such a spatial filtering technology which could resist high power blocking jamming. The technology has been so emphasized for its outstanding performance of anti-jamming. This paper analyzes the application differences of nulling antenna technology between GEO and LEO satellites; a lot of comparison is given. Finally, the application differences are concluded and summarized. [Copyright &y& Elsevier]

Abstract: In order to avoid expensive join operations in query processing from structured XML document, some index methods based on sequence have been proposed, which transform XML documents and twig patterns into sequences. By performing subsequence matching, query is processed holistically without breaking the twig pattern into many individual root-to-leaf paths, and large useless intermediate results and expensive join operations are avoided. In this paper, combining path sequence strategy with region labeling scheme, we propose a new sequence scheme, Region Path sequence scheme, where the last node of each path is labeled with the region labeling scheme. Compared with previous approaches, our approach can avoid false alarm more effectively, and any extra structure for labeling needn’t be constructed. Furthermore, we construct two level B+-tree structure to finish the matching, and also propose corresponding matching algorithm. Experiment results demonstrate that our approach can not only avoid false alarm, but also process query more quickly than previous methods such as ViST, and Constraint Sequence. [Copyright &y& Elsevier]

Abstract: Post combustion absorption technologies represent one of the most commercially ready technologies for CO2 capture. Solvent selection is the critical consideration in post-combustion absorption capture technology. In order to compare the performance of different solvents, it is necessary to perform simulations on a consistent basis and perform a process analysis of the system. The focus of this work was to develop consistent simulations for MEA and K2CO3 systems in ASPEN. The simulations have been developed within the ASPEN RateSep framework and are valid for both natural gas and coal fired power plants. This paper describes the methodology of the simulations and some results from the two systems. The MEA base case was validated with reported values in literature. Potassium carbonate was found to be particularly useful for pressurized combustion and for CO2 removal from product gases of reforming of natural gas or coal. [Copyright &y& Elsevier]