This paper presents an integer discrete cosine transform (IntDCT) with only dyadic values such as k/2n (k, n∈ in N). Although some conventional IntDCTs have been proposed, they are not suitable for lossless-to-lossy image coding in low-bit-word-length (coefficients) due to the degradation of the frequency decomposition performance in the system. First, the proposed M-channel lossless Walsh-Hadamard transform (LWHT) can be constructed by only (log2M)-bit-word-length and has structural regularity. Then, our 8-channel IntDCT via LWHT keeps good coding performance even if low-bit-word-length is used because LWHT, which is main part of IntDCT, can be implemented by only 3-bit-word-length. Finally, the validity of our method is proved by showing the results of lossless-to-lossy image coding in low-bit-word-length.

Recent advances of superconducting single-flux-quantum (SFQ) circuit technology make it attractive to investigate computing systems using SFQ circuits, where arithmetic circuits play important roles. In order to develop excellent SFQ arithmetic circuits, we have to design or select their underlying algorithms, called hardware algorithms, from different point of view than CMOS circuits, because SFQ circuits work by pulse logic while CMOS circuits work by level logic. In this paper, we compare implementations of hardware algorithms for addition by synchronous-clocking SFQ circuits. We show that a set of individual bit-serial adders and Kogge-Stone adder are superior to others.

A generalized Gray map for codes over the ring Fq[u]/ is introduced, where q=pm is a prime power. It is shown that the generalized Gray image of a linear length-N (1-ut)-cyclic code over Fq[u]/ is a distance-invariant linear length-qtN quasi-cyclic code of index qt/p over Fq. It turns out that if (N,p)=1 then every linear code over Fq that is the generalized Gray image of a length-N cyclic code over Fq[u]/, is also equivalent to a linear length-qtN quasi-cyclic code of index qt/p over Fq. The relationship between linear length-pN cyclic codes with (N,p)=1 over Fp and linear length-N cyclic codes over Fp+uFp is explicitly determined.

Quality requirements are scattered over a requirements specification, thus it is hard to measure and trace such quality requirements to validate the specification against stakeholders' needs. We proposed a technique called "spectrum analysis for quality requirements" which enabled analysts to sort a requirements specification to measure and track quality requirements in the specification. In the same way as a spectrum in optics, a quality spectrum of a specification shows a quantitative feature of the specification with respect to quality. Therefore, we can compare a specification of a system to another one with respect to quality. As a result, we can validate such a specification because we can check whether the specification has common quality features and know its specific features against specifications of existing similar systems. However, our first spectrum analysis for quality requirements required a lot of effort and knowledge of a problem domain and it was hard to reuse such knowledge to reduce the effort. We thus introduce domain knowledge called term-characteristic map (TCM) to reuse the knowledge for our quality spectrum analysis. Through several experiments, we evaluate our spectrum analysis, and main finding are as follows. First, we confirmed specifications of similar systems have similar quality spectra. Second, results of spectrum analysis using TCM are objective, i.e., different analysts can generate almost the same spectra when they analyze the same specification.

Electrical contacts are an important part of electrical circuits and many reliability problems are related to electrical contact failure. It is important to investigate the relationship between load and contact resistance which is an important factor of contact reliability. In this study, the effect of plated material and plated thickness on contact resistance was examined. The samples were constructed of a copper alloy with tin or silver plating. Contact configuration was hemispherical-flat contact. The contact resistance was measured by using a four-probe method with a load up to 40 N. The relation between indentation contact area (i.e. apparent contact area) and contact resistance was determined. As experimental results, the contact resistance depends on the indentation of the contact area. In the same contact area, tin-plated samples have higher resistance than those that are silver-plated due to their own resistivity. The constriction resistance of a plated layer, which depends on contact area, plated material and plated thickness, is analyzed by a theoretical solution, which is shown by R=Φρ /2a, using a surface resistance coefficient Φ . The theoretical results show almost good agreement with the experimental results. Thus, the indentation contact area (i.e. apparent contact area) is almost the same as the real contact area in this study.

This paper introduces a coordinate calculation method for a real-time locating system. A ToA algorithm is used to obtain the target node coordinates, but a conventional DC method, which incurs heavy calculation time, is not suitable for embedded systems. This paper proposes the use of a P-control in the PID control algorithm to resolve real-time locating system issues. Performance measures of the accumulated operator number and position error are evaluated. It is shown that the PID method has less calculation and more robust performance than the DC method.

Finding a kernel mapping function for support vector machines (SVMs) is a key step towards construction of a high-performanced SVM-based classifier. While some recent methods exploited an evolutional approach to construct a suitable multifunction kernel, most of them searched randomly and diversely. In this paper, the concept of a family of identical-structured kernel trees is proposed to enable exploration of structure space using genetic programming whereas to pursue investigation of parameter space on a certain tree using evolution strategy. To control balance between structure and parameter search towards an optimal kernel, simulated annealing is introduced. By experiments on a number of benchmark datasets in the UCI and text classification collection, the proposed method is shown to be able to find a better optimal solution than other search methods, including grid search and gradient search.

Effective countermeasures against explosive increase in healthcare expenditures are urgently needed. A paradigm shift in healthcare is called for, and academics and governments worldwide are working hard on the application of information and communication technologies (ICT) as a feasible and effective measure for reducing medical cost. The more prevalent the disease and the easier disease outcome can be improved, the more efficient is medical ICT in reducing healthcare cost. Hypertension and diabetes mellitus are such examples. Chronic heart failure is another disease in which patients may benefit from ICT-based medical practice. It is conceivable that daily monitoring of hemodynamics together with appropriate treatments may obviate the expensive hospitalization. ICT potentially permit continuous monitoring with wearable or implantable medical devices. ICT may also help accelerate the development of new therapeutic devices. Traditionally effectiveness of treatments is sequentially examined by sacrificing a number of animals at a given time point. These inefficient and inaccurate methods can be replaced by applying ICT to the devices used in chronic animal experiments. These devices allow researchers to obtain biosignals and images from live animals without killing them. They include implantable telemetric devices, implantable telestimulation devices, and imaging devices. Implanted rather than wired monitoring and stimulation devices permit experiments to be conducted under even more physiological conditions, i.e., untethered, free-moving states. Wireless communication and ICT are indispensible technologies for the development of such telemetric and telestimulation devices.

In recent years, digital maps have been used in a variety of scenarios, including car navigation systems and map information services over the Internet. These digital maps are formed by multiple layers of maps of different scales; the map data most suitable for the specific situation are used. Currently, the production of map data of different scales is done by hand due to constraints related to processing time and accuracy. We conducted research concerning technologies for automatic generation of simplified map data from detailed map data. In the present paper, the authors propose the following: (1) a method to transform data related to streets, rivers, etc. containing widths into line data, (2) a method to eliminate the component points of the data, and (3) a method to eliminate data that lie below a certain threshold. In addition, in order to evaluate the proposed method, a user survey was conducted; in this survey we compared maps generated using the proposed method with the commercially available maps. From the viewpoint of the amount of data reduction and processing time, and on the basis of the results of the survey, we confirmed the effectiveness of the automatic generation of simplified maps using the proposed methods.

In this paper, we present an effective overlay real-time video multicast system over the Internet. The proposed system effectively integrates overlay multicast technology and video compression technology. Overlay multicast tree and target bit rate are determined to satisfy the given average delay constraint, and H.263+ rate control is implemented to enhance the human visual perceptual quality over the multicast tree. Finally, experimental results are provided to show the performance of the proposed overlay video multicast system over the Internet.

This paper presents a high-speed Forward Error Correction (FEC) architecture based on concatenated Bose-Chaudhuri-Hocquenghem (BCH) for 100-Gb/s optical communication systems. The concatenated BCH code consists of BCH(3860, 3824) and BCH(2040, 1930), which provides 7.98 dB net coding gain at 10-12 corrected bit error rate. The proposed BCH decoder features a low-complexity key equation solver using an error-locator computation RiBM (ECRiBM) algorithm and its architecture. The proposed concatenated BCH-based Super-FEC architecture has been implemented in 90-nm CMOS standard cell technology with a supply voltage of 1.1 V. The implementation results show that the proposed architecture can operate at a clock frequency of 400 MHz and has a throughput of 102.4-Gb/s for 90-nm CMOS technology.

This letter presents an approach to the construction of multiple-rate quasi-cyclic (QC) low-density parity-check (LDPC) codes based on hyperplanes (µ-flats) of two different dimensions in Euclidean geometries. The codes constructed with this method have the same code length, multiple-rate and large stopping sets while maintaining the same basic hardware architecture. The code performance is investigated in terms of the bit error rate (BER) and compared with those of the LDPC codes which are proposed in IEEE 802.16e standard. Simulation results show that our codes perform very well and have low error floors over the AWGN channel.

A multiple-peak negative differential resistance (NDR) circuit made of standard Si-based metal-oxide-semiconductor field-effect-transistor (MOS) and SiGe-based heterojunction bipolar transistor (HBT) is demonstrated. We can obtain a three-peak I-V curve by connecting three cascoded MOS-HBT-NDR circuits by suitably designing the MOS parameters. This novel three-peak NDR circuit possesses the adjustable current-voltage characteristics and high peak-to-valley current ratio (PVCR). We can adjust the PVCR values to be as high as 11.5, 6.5, and 10.3 for three peaks, respectively. Because the NDR circuit is a very strong nonlinear element, we discuss the extrinsic hysteresis phenomena in this multiple-peak NDR circuit. The effect of series resistance on hysteresis phenomena is also investigated. Our design and fabrication of the NDR circuit is based on the standard 0.35 µm SiGe BiCMOS process.

We propose requirement validation criteria and a method based on the interaction between actors in an information system. We focus on the cyclical transitions of one actor's situation against another and clarify observable stimuli and responses based on these transitions. Both actors' situations can be listed in a state transition table, which describes the observable stimuli or responses they send or receive. Examination of the interaction between both actors in the state transition tables enables us to detect missing or defective observable stimuli or responses. Typically, this method can be applied to the examination of the interaction between a resource managed by the information system and its user. As a case study, we analyzed 332 requirement defect reports of an actual system development project in Japan. We found that there were a certain amount of defects regarding missing or defective stimuli and responses, which can be detected using our proposed method if this method is used in the requirement definition phase. This means that we can reach a more complete requirement definition with our proposed method.

Nonlinear distortions in power amplifiers (PAs) generate spectral regrowth at the output, which causes interference to adjacent channels and errors in digitally modulated signals. This paper presents a novel method to evaluate adjacent channel leakage power ratio (ACPR) and error vector magnitude (EVM) from the amplitude-to-amplitude (AM/AM) and amplitude-to-phase (AM/PM) characteristics. The transmitted signal is considered to be complex Gaussian distributed in orthogonal frequency-division multiplexing (OFDM) systems. We use the Mehler formula to derive closed-form expressions of the PAs output power spectral density (PSD), ACPR and EVM for memoryless PA and memory PA respectively. We inspect the derived relationships using an OFDM signal in the IEEE 802.11a WLAN standard. Simulation results show that the proposed method is appropriate to predict the ACPR and EVM values of the nonlinear PA output in OFDM systems, when the AM/AM and AM/PM characteristics are known.

This paper presents an autonomous navigation system for a mobile robot using randomly distributed passive RFID tags. In the case of randomly distributed RFID tags, it is difficult to provide the precise location of the robot especially in the area of sparse RFID tag distribution. This, combined with the wide turning radius of the robot, can cause the robot to enter a zigzag exploration path and miss the goal. In RFID-based navigation, the key is to reduce both the number of RFID tags and the localization error for practical use in a large space. To cope with these, we utilized the Read time, which measures the reading time of each RFID tag. With this, we could estimate accurately the localization and orientation without using any external sensors or increasing the RFID tags. The average estimation errors of 7.8 cm in localization and 11 degrees in orientation were achieved with 102 RFID tags in the area of 4.2 m by 6.2 m. Our proposed method is verified with the path trajectories produced during navigation compared with conventional approaches.

This paper studies the feasibility of 700 MHz band inter-vehicle communication system when it is put into practical use in urban area. To verify the system, a large-scale demonstration experiment in a quasi-street test course is performed. In the experiment, a number of vehicles which are equipped with communication devices conforming to ITS FORUM RC-006 specifications are employed. A simulation method that is applicable to large-scale communication model is also designed, and the validity of the method is verified by utilizing the results derived from the experiment. Based on this model, the quality of the inter-vehicle communication system in urban area communication environment is estimated. The results show that the system's performance satisfies the requirements of representative prevention scenes of traffic accident, and the feasibility of the 700 MHz band inter-vehicle communication system specified in RC-006 is verified in the practical use in urban communication environment.

In this letter, DFT-based channel estimation (CE) with a strong interference detector is proposed for OFDM systems. Computer simulations demonstrate that the proposed scheme achieves similar performance to an interference-free system and is a significant enhancement over conventional methods.

Hierarchical Identity-Based Encryption (HIBE) is a generalization of identity-based encryption that mirrors an organizational hierarchy, and allows the root Private Key Generator (PKG) to distribute the workload of key generations to lower-level PKGs. In Indocrypt'08, Ren and Gu proposed a new HIBE scheme, and claimed that their scheme is fully chosen-ciphertext secure in the standard model. However, by giving a concrete attack, we show that Ren-Gu's HIBE is even not chosen-plaintext secure.

Superconducting Quantum Interference Devices (SQUIDs) are known to be the most sensitive magnetometers, used in a wide range of applications like biomagnetism, geomagnetism, Non Destructive Evaluation (NDE), metrology or fundamental science. For all these applications, the SQUID sensor is used in analog mode and associated with a carefully designed room-temperature control and/or feedback electronics. Nevertheless, the use of SQUID sensors in digital mode is of high interest for several applications due to their quantum accuracy associated to high linearity, and their potentially very high slew rate and dynamic range. The concept and performances of a low-Tc digital magnetometer based on Single-Flux-Quantum (SFQ) logic, fabricated at the FLUXONICS Foundry located at IPHT Jena, Germany, are given after a presentation of the context of development of superconductive digital magnetometers. The sensitivity, limited to one magnetic single flux quantum, and a dynamic range of 76 dB, that corresponds to an upper limit of the magnetic field amplitude higher than 5 µT, have been measured along with overnight stability. The dynamic range of about 2800 magnetic flux quanta Φ0 has been experimentally observed with an external magnetic field. First signatures of magnetic fields have been observed simultaneously with the ones of analog SQUIDs in the low noise environment of the Laboratoire Souterrain a Bas Bruit (LSBB) located in Rustrel, Provence, France.