This paper proposes a new Ad-Hoc network system which comprises the multiple relay access points (APs) with multi channels. Ad-Hoc network systems are recently proposed and incorporated for the communication infrastructure, which relays wireless transmission among access points (APs) in wireless LAN (WLAN) system. System throughput is decreased due to hidden terminal problem when only a single channel is used for the Ad-Hoc network. In order to solve this problem, a new system with multi channels is proposed. However, even if the multi channels are employed, the co- and/or adjacent-channel interference occurs due to hidden terminal problem and multiple APs in a limited space, when considering a simultaneous transmit and reception at the relay AP. In this paper, we develop an Ad-Hoc network testbed which can reduce and avoid co- and/or adjacent-channel interference by using vertically arranged antenna configuration and distributed channel allocation scheme. Moreover, the effectiveness of our testbed is clarified by applying actual WLAN signals.

Flash SSDs are being incorporated in many enterprise storage platforms recently and expected to play a notable role for IO-intensive applications. However, the IO characteristics of flash SSDs are very different from those of hard disks. Since existent storage subsystems are designed on the basis of characteristics of hard disks, the IO performance of flash SSDs may not be obtained as expected. This paper provides an evaluation of flash SSDs in transaction processing systems with TPC-C benchmark. We present performance results with various configurations and describe our observations of the IO behaviors at different levels along the IO path, which helps to understand the performance of flash-based transaction processing systems and provides certain references to build flash-based systems for IO-intensive applications.

This paper proposes a new semantics that characterizes the time and/or situation dependencies of properties, together with the ontological notion of existential rigidity. For this purpose, we present order-sorted tempo-situational logic (OSTSL) with rigid/anti-rigid sorts and an existential predicate. In this logic, rigid/anti-rigid sorted terms enable the expressions for sortal properties, and temporal and situational operators suitably represent the ontological axioms of existential rigidity and time and/or situation dependencies. A specific semantics of OSTSL adheres to the temporal and situational behaviors of properties based on existential rigidity. As a result, the semantics guarantees that the ontological axioms of properties expressed by sorted tempo-situational formulas are logically valid.

Wireless access networks of the future could provide a variety of context-aware services with the use of sensor information in order to solve regional social problems and improve the quality of residents' lives as a part of the regional infrastructure. NerveNet is a conceptual regional wireless access platform in which multiple service providers provide their own services with shared use of the network and sensors, enabling a range of context-aware services. The platform acts like a human nervous system. Densely located, interconnected access points with databases and data processing units will provide mobility to terminals without a location server and enable secure sensor data transport on a highly reliable, managed mesh network. This paper introduces the motivations, concept, architecture, system configuration, and preliminary performance results of NerveNet.

In this paper, we introduce a new sequential pattern, the Interactive User Sequence Pattern (IUSP). This pattern is useful for grouping highly interrelated users in one-way communications such as e-mail, SMS, etc., especially when the communications include many spam users. Also, we propose an efficient algorithm for discovering IUSPs from massive one-way communication logs containing only the following information: senders, receivers, and dates and times. Even though there is a difficulty in that our new sequential pattern violates the Apriori property, the proposed algorithm shows excellent processing performance and low storage cost in experiments on a real dataset.

A regulation of converters connected in parallel is discussed considering their stored energy and passivity characteristics. From the viewpoint of stored energy, a new regulation method to conserve and share the stored energy can be found. The energy stored in inductors and capacitors is transferred to loads so that the load keeps the energy dissipation constant. Though numerical simulation, the method is validated for a parallel converter system.

The extended binary phase shift keying (EBPSK) transmission system with ultra narrow bandwidth has excellent BER performance, which raises many doubts with the researchers. Therefore, on the premise of the existence of a special filter that can transform the modulated phase information into amplitude information, the theoretical BER formula of EBPSK system in Additive White Gaussian Noise (AWGN) channel has been deduced. This paper gives the theoretical values of the parameters in the above BER formula and discusses the effects of parameters on BER firstly. Then the paper shows that the special impacting filter satisfies the above assumption, therefore, in the frame of binary detection theory, the excellent performance of high-efficiency EBPSK system can be explained and the correction of the theoretical BER formula can be validated.

Bandwidth is an extremely valuable and scarce resource in multimedia networks. Therefore, efficient bandwidth management is necessary in order to provide high Quality of Service (QoS) to users. In this paper, a new QoS-aware bandwidth allocation algorithm is proposed for the efficient use of available bandwidth. By using the multi-objective optimization technique and Talmud allocation rule, the bandwidth is adaptively controlled to maximize network efficiency while ensuring QoS provisioning. In addition, we adopt the online feedback strategy to dynamically respond to current network conditions. With a simulation study, we demonstrate that the proposed algorithm can adaptively approximate an optimized solution under widely diverse traffic load intensities.

Effect of an addition of a cooled step-up transformer to a flux locked loop (FLL) circuit was studied to reduce indirect rf interference to HTS-dc-SQUID. First, we demonstrated that a noise level of an HTS-dc-SQUID system using the FLL circuit with single room-temperature transformer could be easily degraded by radiation of rf electromagnetic wave to cables in the FLL circuit. It is thought that the rf radiation induced rf current in the circuit, and was transmitted to the SQUID to modulate the bias current, resulting in the increase of the noise level. To avoid the degradation due to such indirect rf interference, the cooled set-up transformer was added to the FLL circuit since it was expected that the additional transformer would work as a "step-down" transformer against the induced rf current. It was shown that the noise level of a HTS-SQUID system (SQUITEM system) operated in an electromagnetically unshielded environment could be improved to the same level as that measured in a magnetically shielded room by the additional cooled transformer and appropriate impedance matching.

A 1.8 V, 5 GHz low power frequency synthesizer for Wireless Sensor Networks is presented in 0.18 µm CMOS technology. A low power phase-switching prescaler is designed, and the current mode phase rotator is merged into the first divide-by-2 circuit of the prescaler to reduce power and propagation delay. An improved charge pump circuit is proposed to compensate for the dynamic effects with the charge pump. By a divide-by-2 circuit, the frequency synthesizer can provide a 2.324-2.714 GHz quadrature output frequency in 1 MHz steps with a 4 MHz reference frequency. The measured output phase noise is -110 dBc/Hz at 1-MHz offset frequency. The power consumption of the PLL is 11.2 mW at 1.8 V supply voltage.

Improving quality of healthcare for people with chronic conditions requires informed and knowledgeable healthcare providers and patients. Decision support and clinical information system are two of the main components to support improving chronic care. In this paper, we describe an ontology-based information and knowledge management framework that is important for chronic disease care management. Ontology-based knowledge acquisition and modeling based on knowledge engineering approach provides an effective mechanism in capturing expert opinion in form of clinical practice guidelines. The framework focuses on building of healthcare ontology and clinical reminder system that link clinical guideline knowledge with patient registries to support evidenced-based healthcare. We describe implementation and approaches in integrating clinical reminder services to existing healthcare provider environment by focusing on augmenting decision making and improving quality of patient care services.

Distributed hash tables (DHTs) enable companies or campuses to use voice over IP (VoIP) systems in private networks at low cost. However, DHTs incur latency stretch caused by a topology mismatch between the application layer and the physical layer. Reducing this latency stretch is critical when implementing real-time applications that use DHTs, such as VoIP systems. This letter proposes a new method for reducing the latency stretch by creating node IDs, which form structured overlays that consider node proximity. Simulation results show that the proposed method is superior to Chord in terms of the distance between nodes, look-up path length, network burden, and look-up latency.

Based on sliding-window rule application and extraction filtering, we present a framework for extracting multi-slot frames describing chemical reactions from Thai free text with unknown target-phrase boundaries. A supervised rule learning algorithm is employed for automatic construction of pattern-based extraction rules from hand-tagged training phrases. A filtering method is devised for removal of incorrect extraction results based on features observed from text portions appearing between adjacent slot fillers in source documents. Extracted reaction frames are represented as concept expressions in description logics and are used as metadata for document indexing. A document knowledge base supporting semantics-based information retrieval is constructed by integrating document metadata with domain-specific ontologies.

This letter presents an experiment for estimating accurate state in distributed power systems. This letter employs a technique that combines a projected Jacobi method with a parallel dual-type method to solve the distributed state estimation with constraints problems. Via numerous tests, this letter demonstrates the efficiency of the proposed method on the IEEE 118-bus with four subsystems in a PC network.

In this paper, we present a specific type of irreducible polynomial which is an irreducible m-term polynomial of degree m. Designing the parallel multiplier over GF(2m) by the quadrinomial obtained from this irreducible polynomial, its critical delay path is smaller than that of conventional multipliers for some degree m.

In this paper, we propose a method for robot self-position identification by active sound localization. This method can be used for autonomous security robots working in room environments. A system using an AIBO robot equipped with two microphones and a wireless network is constructed and used for position identification experiments. Differences in arrival time to the robot's microphones are used as localization cues. To overcome the ambiguity of front-back confusion, a three-head-position measurement method is proposed. The position of robot can be identified by the intersection of circles restricted using the azimuth differences among different sound beacon pairs. By localizing three or four loudspeakers as sound beacons positioned at known locations, the robot can identify its position with an average error of 7 cm in a 2.53.0 m2 working space in the horizontal plane. We propose adjusting the arrival time differences (ATDs) to reduce the errors caused when the sound beacons are high mounted. A robot navigation experiment was conducted to demonstrate the effectiveness of the proposed position-identification system.

In order to accelerate yield improvement in semiconductor manufacturing, it is important to prevent the root causes of product-specific failures, such as systematic defects and parametric defects, which are different for each product. We herein propose a method for the investigation of product-specific failures by estimating differences between the actual failing bit signatures (FBSs) and the predicted FBSs caused by random defects. In order to estimate these differences accurately, we have developed a novel algorithm by which to extract the critical area for each FBS. The total failure rate errors of FBSs are within 0.5% for embedded SRAMs. The proposed method identified the root causes of product-specific failures in 150 and 65 nm technology node products.

Let Q be the set of all primitive words over a finite alphabet having at least two letters. In this paper, we study the language D(1) of all non-overlapping (d-primitive) words, which is a proper subset of Q. We show that D(1) is a context-sensitive langauage but not a deterministic context-free language. Further it is shown that [D(1)]n is not regular for n ≥ 1.

In JPEG2000, the Cohen-Daubechies-Feauveau (CDF) 9/7-tap wavelet filter was implemented by using the conventional lifting scheme. However, the filter coefficients remain complex, and the conventional lifting scheme disregards image edges in the coding process. In order to solve these issues, we propose a lifting scheme in two steps. In the first step, we select the appropriate filter coefficients; in the second step, we employ a median operator to regard image edges. Experimental results show that the peak signal-to-noise ratio (PSNR) value of the proposed lifting scheme is significantly improved, by up to 0.75 dB on average, compared to that of the conventional lifting scheme in the CDF 9/7-tap wavelet filter of JPEG2000.

This paper presents a syntax-based framework for gap resolution in analytic languages. CCG, reputable for dealing with deletion under coordination, is extended with a memory mechanism similar to the slot-and-filler mechanism, resulting in a wider coverage of syntactic gaps patterns. Though our grammar formalism is more expressive than the canonical CCG, its generative power is bounded by Partially Linear Indexed Grammar. Despite the spurious ambiguity originated from the memory mechanism, we also show that its probabilistic parsing is feasible by using the dual decomposition algorithm.