Decision Support Systems (DSS) are a specific class of computerized information system that support business and organizational decision-making activities. They help decision makers compile useful information from raw data, documents, personal knowledge, and/or business models to identify and solve problems and make decisions. "Decision Support System for the Crystallization Unit of a Sugar Plant", contributed by P C Tewari et al., presents a Decision Support System (DSS) for the crystallization unit of a sugar plant. The decision support system has been developed with the help of a mathematical modeling using simple probabilistic approach. The decision matrices are also developed, which provide various availability levels for different combinations of failure and repair rates of each subsystem of the crystallization unit. The authors conclude that the crystallizer is the most critical subsystem as far as maintenance work is concerned and should be given top priority for the repairs, as the effect of its failure/repair rates on system availability is much higher than that of centrifuge and sugar grader subsystems.

Advanced Encryption Standard (AES) is used extensively nowadays in many network and multimedia applications to address security issues. The Rijndael Algorithm, developed by Joan Daemen and Vincent Rijmen, has been approved by the US National Institute of Standards and Technology (NIST) as the new (AES). As this block cipher is expected to be widely used in an extensive variety of products, its efficient implementation becomes a significant priority. Software implementations of cryptographic algorithms cannot provide the necessary performance when large amounts of data have to be moved with a very high speed. Efficient hardware implementation is, by nature, more physically secure than software implementation. The three major design targets with respect to hardware realization are: optimization for area or cost, low latency that minimizes time to encrypt a single block, and high throughput to encrypt multiple blocks in parallel. All these design criteria involve a tradeoff between area and speed. In the paper, "Area Efficient FPGA Implementation of AES-128", Arti Noor et al., have reported the two AES architectures and their VLSI implementations. Reducing the hardware requirement and achieving high-speed performance without compromising on the security are the objectives of the work. Using VirtexE, two different key expansion units of both architecture have been designed and implemented on xcv300e-7bg432 FPGA. The first architecture is the use of a feedback structure for key generation, less area requirement, less latency and less throughput. High speed, high throughput with more hardware requirement are the salient features of the second architecture using memory for key storage.

In applications where size, weight, cost, performance, ease of installation, and aerodynamic profile are constraints, low profile antennas like microstrip antennas are required. One of the serious limitations of these antennas has been their narrow impedance bandwidth characteristic. S L Mallikarjun et al., in their paper titled, "Design and Development of Wideband High Gain Microstrip Patch Antenna", have reported the design and fabrication of two, three and four slots rectangular microstrip antennas. These antennas are reported to show improved impedence bandwidth and gain at X-band frequencies. These compact and wideband antennas may find application in high frequency WLAN and mobile computing networks.

"SystemC-Based Design Approach for Modeling Reconfigurable Computing Systems", by Rana Mukherji, has proposed a SystemC-based approach for system-level modeling of reconfigurable hardwares. In the face of General Purpose MicroProcessors (GPPs) and Field Programmable Gate Arrays (FPGAs) not being able to cope with the growing demands for higher computational power, reconfigurable system turns out to be a promising alternative to deliver both flexibility and performance. Due to its potential to greatly accelerate a wide variety of applications, reconfigurable computing has become a subject of a great deal of research. Its key feature is the ability to perform computations in hardware to increase performance, while retaining much of the flexibility of a software solution. For designing of reconfigurable parts, systemC is selected as the backbone since it is a standard language that provides designers with basic mechanisms like channels and interfaces found in system designs. Owing to open source reference implementation, it becomes the natural choice of system architects and designers. In this paper, the author has discussed a design approach of SystemC (a C++ class library) for RCS at the system-level which provides the necessary features for modeling design hierarchy, concurrency and reactivity in hardware.

A case study titled "Total Productive Maintenance (TPM): An Operational Efficiency Tool", by M S Prabhuswamy et al., have illustrated the effect of TPM implementation in the grinding operation of the manufacturing process in an automotive industry. It is quantitatively demonstrated that all parameters contributing to the overall equipment efficiency (OEE) improve on the implementation of TPM.

Dark matter is now generally believed to be the dominating mass component of the universe, starting with the discovery of Zwicky (1933) that the speed of galaxies in the coma cluster is too large to keep them gravitationally bound unless they are much heavier than one would estimate on the basis of visible matter alone. Newtonian gravity applied to galaxies and galaxy clusters leads to much higher mass estimates than expected from the observed stars and galaxy cluster. This discrepancy is again explained by the theory that dark matter and dark energy make up most of the universe. Cold dark matter simulation using NFW (Navarro-Frenk-White) model fit well with the evolution of large-scale structure of universe but disagree with observations on small- scale distances. Rakesh Sharma et al., in the paper titled "On Interaction in Dark Matter", have opted a modified gravitational interaction approach, taking into account the screening effect of surrounding masses, and get a much weaker binding energy than given by the standard dynamics and NFW. The authors conclude that many of the observations in the galactic space, including fluctuations in the density of galaxies and clusters, may be ascribed to the screening of dark matter.

- Elizabeth Zacharias
Consulting Editor