We have analyzed the dominant noise sources in the driving circuit of an uncooled infrared radiation focal plane array fabricated on a silicon-on-insulator (SOI) substrate by 0.35 µm CMOS technology and bulk- micromachining. We found no noise property of SOI-MOSFET inferior compared to those of NMOSs formed on SOI and bulk substrate, respectively. In addition, we reduced the total noise of the sensor chip by designing the current source NMOS sufficiently large, and optimized the operating current of pixel pn-junctions.

Internet computing is proposed to exploit personal computing resources across the Internet in order to build large-scale Web applications at lower cost. In this paper, a DHT-based distributed Web crawling model based on the concept of Internet computing is proposed. Also, we propose two optimizations to reduce the download time and waiting time of the Web crawling tasks in order to increase the system's throughput and update rate. Based on our contributor-friendly download scheme, the improvement on the download time is achieved by shortening the crawler-crawlee RTTs. In order to accurately estimate the RTTs, a network coordinate system is combined with the underlying DHT. The improvement on the waiting time is achieved by redirecting the incoming crawling tasks to light-loaded crawlers in order to keep the queue on each crawler equally sized. We also propose a simple Web site partition method to split a large Web site into smaller pieces in order to reduce the task granularity. All the methods proposed are evaluated through real Internet tests and simulations showing satisfactory results.

The principles for good design of battery-aware voltage scheduling algorithms for both aperiodic and periodic task sets on dynamic voltage scaling (DVS) systems are presented. The proposed algorithms are based on greedy heuristics suggested by several battery characteristics and Lagrange multipliers. To construct the proposed algorithms, we use the battery characteristics in the early stage of scheduling more properly. As a consequence, the proposed algorithms show superior results on synthetic examples of periodic and aperiodic tasks from the task sets which are excerpted from the comparative work, on uni- and multi-processor platforms, respectively. In particular, for some large task sets, the proposed algorithms enable previously unschedulable task sets due to battery exhaustion to be schedulable.

Switch and stay combining (SSC) is an attractive diversity technique due to its low complexity and compatibility to resource-constrained wireless networks. This letter proposes a distributed SSC for partial relay selection networks in order to achieve spatial diversity as well as to improve spectral efficiency. Simulation results show that the performance loss (in terms of bit error probability) of the proposed networks relative to partial relay selection networks with selection combining is not substantial.

Platforms of hosting services are expected to provide a virtual private computing infrastructure with guaranteed levels of performance to support each reservation request sent by a client. To enhance the performance of the computing infrastructure in responding to reservation requests, the platforms are required to reserve, coordinate, and control globally distributed computing and network resources across multiple domains. This paper proposes Grid Network Service -- Web Services Interface version 2 (GNS-WSI2). GNS-WSI2 is a resource-reservation messaging protocol that establishes a client-server relationship. A server is a kind of management system in the management plane, and it allocates available network resources within its own domain in response to each reservation request from a client. GNS-WSI2 has the ability to reserve network resources rapidly and reliably over multiple network domains. This paper also presents the results of feasibility tests on a transpacific testbed that validate GNS-WSI2 in terms of the scalable reservation of network resources over multiple network domains. In the tests, two computing infrastructures over multiple network domains are dynamically provided for scientific computing and remote-visualization applications. The applications are successfully executed on the provided infrastructures.

In this paper, we propose a genetic algorithm (GA) based equalization approach for direct sequence ultra-wideband (DS-UWB) wireless communication systems, where the GA is combined with a RAKE receiver to combat the inter-symbol interference (ISI) due to the frequency selective nature of UWB channels for high data rate transmission. The proposed GA based equalizer outperforms significantly the RAKE and the RAKE-minimum mean square error (MMSE) receivers according to results obtained from intensive simulation work. The RAKE-GA receiver also provides bit-error-rate (BER) performance very close to that of the optimal RAKE-maximum likelihood detection (MLD) approach, while offering a much lower computational complexity.

Bandwidth and gain enhancement of microstrip patch antennas (MPAs) is proposed using reflective metasurface (RMS) as a superstrate. Two different types of the RMS, namely- the double split-ring resonator (DSR) and double closed-ring resonator (DCR) are separately investigated. The two antenna prototypes were manufactured, measured and compared. The experimental results confirm that the RMS loaded MPAs achieve high-gain as well as bandwidth improvement. The desinged antenna using the RMS as a superstrate has a high-gain of over 9.0 dBi and a wide impedance bandwidth of over 13%. The RMS is also utilized to achieve a thin antenna with a cavity height of 6 mm, which is equivalent to λ/21 at the center frequency of 2.45 GHz. At the same time, the cross polarization level and front-to-back ratio of these antennas are also examined.

Broadband antennas have various applications in digital terrestrial television (DTV) services. Compact broadband antennas are required for arranging in long and narrow space along the rim of a laptop display. A leaky-wave antenna using the composite right/left-handed transmission line (CRLH-TL) is one of the candidates for achieving the broadband antenna. However, there are not enough to design guideline of small leaky wave antennas using the CRLH-TL for UHF band. In this paper, a CRLH-TL comprising a ladder network is proposed for broadband and simple structure. The paper also discusses the design of a leaky-wave antenna with the CRLH-TL operating in the DTV band. The relation between the operating bandwidth and attenuation constant of the CRLH-TL is discussed. An antenna that can be accommodated in the limited and narrow space available in mobile terminals has to be designed. Hence, the effects of the number of cells and a finite ground plane are discussed with the purpose of achieving the miniaturization of the antenna. In this study, the transmission and radiation characteristics of the fabricated antennas are measured. The gain of the fabricated antenna is confirmed to remain almost constant even when the operating frequency is varied. The maximum gain and operating band achieved in this study are approximately -0.6 dBi and about 54%, respectively.

The hybrid antenna consisted of cylindrical dielectric resonator and rectangular slot was implemented. The hybrid antenna resonated at two different frequencies. The lower resonant frequency was associated with the rectangular slot while the higher resonant frequency was associated with the cylindrical dielectric resonator. Parametric investigation was carried out using simulation software. The proposed hybrid antenna had good agreement between the simulation and measurement results. A 24% bandwidth (return loss < 10 dB) of 2.30 GHz, and a 18% bandwidth (return loss < 10 dB) of 5.46 GHz was implemented successfully for application in ISM and UNII band.

In a ZigBee network, a finite address space is allocated to every potential parent device and a device may disallow a join request once this address space is exhausted. When a new node (child) requests to a coordinator (parent) to join a ZigBee network, the coordinator checks its address space. If it has sufficient address space, the coordinator accepts the new node as its child in the ZigBee network. If the new node has router capability (JoinAsRouter), it becomes a router in the ZigBee network. However, this association procedure makes ZigBee networks inefficient for routing, because the coordinator checks only the maximum and current numbers of child nodes. In the worst case, the network will be arranged so that the router nodes are crowded in the network. Therefore, we propose the KMCD-IME (Keeping the Maximum Communication Distance and Initial Mutual Exclusion among router nodes) algorithm with two additional conditions when a new node joins the ZigBee network. The first condition maintains the maximum communication distance between the new node and the would-be parent node. The second condition is the Initial Mutual Exclusion among router nodes. The router nodes are evenly spread across the network by KMCD-IME and an effective routing topology is formed. Therefore, the KMCD-IME algorithm extends the lifetime of the ZigBee network.

A method was developed for analyzing a system comprised of identical and indistinguishable elements with nonlinear dynamics. First, a moment vector equation (MVE) for the system was derived so as to avoid the curse of dimensionality by using the property that the elements are identical and indistinguishable. Next, an algorithm was developed to solve the MVE for deriving the moment vector in a steady state. It effectively uses eigen analysis on the basis of the property of the MVE. It can thus be used to clarify the structure of the solutions in the moment vector space and to derive multiple solutions by setting the initial value to the moment vector orthogonal to the solutions already obtained. Finally, the probability density function (pdf) for the state of the system was derived using the moment vectors in a steady state. Comparison of the pdfs thereby derived with those derived using numerical simulation showed that the method provided good approximations of the pdfs. Moreover, multiple solutions that are difficult to do using numerical simulation were derived.

Recently a simple proof of Jury test for complex polynomials was given by the author. In this letter further extended results are presented. Another elementary proof of the Schur stability condition is provided. More importantly it is shown that the stability table can also be used to determine the root distribution of complex polynomials with respect to the unit circle in the complex plane.

In this paper, we analyze the performance of the 21 Alamouti scheme suggested by Alamouti, composed of the transmit space-time code and the simple linear decoding processing, in perfectly time-varying and spatially correlated channels. We derive the closed-form probability density function (PDF) of output signal-to-noise ratio (SNR) and outage probability of the Alamouti scheme as a function of spatial correlation coefficient in the consideration of no correlation in time. We observe that the performance of the Alamouti scheme is severely degraded when the channels are time-varying and spatially correlated.

Various contrast enhancement methods such as histogram equalization (HE) and local contrast enhancement (LCE) have been developed to increase the visibility and details of a degraded image. We propose an image contrast enhancement method based on the global and local adjustment of gray levels by combining HE with LCE methods. For the optimal combination of both, we introduce a discrete entropy. Evaluation of our experimental results shows that the proposed method outperforms both the HE and LCE methods.

CMOS SoCs can reduce power consumption by adopting voltage scaling (VS) technologies, where the level converter (LC) is required between voltage domains to avoid dc current. However, the LC often induces high delay penalty and usually results in non-balanced rise and fall delays. Therefore, the performance of the LC strongly affects the effectiveness of VS technologies. In this paper, heuristic sizing methodology for designing a state-of-the-art LC is developed and proposed. Using the proposed methodology, we can design the LC to achieve high performance with balanced rise and fall delay times in a deterministic way.

This letter considers power-controlled transmission from directional antennas in mmWave wireless personal area network (WPAN) systems. The attributes of these systems are studied; these include the number of concurrent transmissions and the power consumption with different system parameters, such as the antenna's beamwidth and radiating efficiency. Numerical results are presented to show that the power controlled transmission enables more concurrent transmissions than the non-power controlled transmission. The results also show that the number of concurrent transmissions increases as the beamwidth and the path loss component become smaller and the antenna's radiating efficiency increases. In addition, the power controlled system generally uses less power than the non-power controlled transmission set up; the overall analysis is verified by simulation.

We propose a scheme of MultiCast Routing and Wavelength Assignment (MC-RWA) to establish light-tree for dynamic multicast session for the Wavelength Division Multiplex (WDM) network by choosing the wavelength that leads to a reduction in blocking probabilities by using a parameter Δ. Δ is defined as the overall reduction of connectivity of the nodes in the network caused by a wavelength assignment process when using a particular wavelength, and we assign wavelength resources to the multicast session by choosing the Δ which leads to smallest reduction in connectivity. Through computer simulation, we show that the proposed scheme has lower blocking probabilities when compared with minimum cost scheme under the condition that wavelength conversion is not allowed.

In this paper a nonlinearity compensation algorithm based on the extended Kalman filter is proposed to improve the measurement accuracy of a heterodyne laser interferometer. The heterodyne laser interferometer is used for ultra-precision measurements such as those used in semiconductor manufacturing. However the periodical nonlinearity property caused by frequency-mixing restricts the accuracy of the nanometric measurements. In order to minimize the effect of the nonlinearity, the measurement process of the laser interferometer is modeled as a state equation and the extended Kalman filtering approach is applied to the process. The effectiveness of our proposed algorithm is demonstrated by comparing the results of the algorithm with experimental results for the laser system.

Simple power analysis (SPA) can be employed in examining the power consumption trace of elliptic curve scalar multiplication to retrieve the computational sequence. However, SPA cannot distinguish point addition from point subtraction. The attacker still requires an exhaustive search to recover the private key when it is recoded in NAF or recoded by the 2-bit sliding window method. The average Hamming weight of an n-bit NAF recoded scalar is n/3, and an exhaustive search among the 2n/3 candidates is required. This paper shows that in a left-to-right NAF recoded or a left-to-right 2-bit sliding window manipulated scalar the relative position of nonzero bits will reveal their values. Our analysis skill reduces the number of candidates of the scalar from the naive search of 2n/3 to 22n/9 and 20.19n respectively for the cases of NAF and sliding window method.

The exact time complexity of Hsu and Huan's self-stabilizing maximal matching algorithm is provided. It is n2 + n - 2 if the number of nodes n is even and n2 + n - if n is odd.