This paper proposes a thresholding based segmentation method aided by Kleene Algebra. For a given image including some regions of interest (ROIs for short) with the coherent intensity level, assume that we can segment each ROI on applying thresholding technique. Three segmented states are then derived for every ROI: Shortage denoted by logic value 0, Correct denoted by 1 and Excess denoted by 2. The segmented states for every ROI in the image can be then expressed on a ternary logic system. Our goal is then set to find "Correct (1)" state for every ROI. First, unate function, which is a model of Kleene Algebra, based procedure is proposed. However, this method is not complete for some cases, that is, correctly segmented ratio is about 70% for three and four ROI segmentation. For the failed cases, Brzozowski operations, which are defined on De Morgan algebra, can accommodate to completely find all "Correct" states. Finally, we apply these procedures to segmentation problems of a human brain MR image and a foot CT image. As the result, we can find all "1" states for the ROIs, i. e. , we can correctly segment the ROIs.

Although there are many multimedia presentation systems on the market, they have some shortcomings and most of them only can work on one single computer, and few of them can work on Web. Thus, in the thesis we develop a network multimedia presentation system to let users easily design the multimedia presentation without restriction on technology or presentation time and place. Our system includes 3 main components: User Interface that includes temporal specification editor, spatial specification editor and multimedia object interface, Presentation Interface and Knowledge Base. There is a dynamic homepage generator in our system and we propose a displaying algorithm based on the Allen's theory, that there exist 13 temporal relationships between two intervals, for synchronizing the media objects.

A model of the prefrontal cortical circuit has been constructed to investigate the dynamics for working memory processing. The model circuit is multi-layered and consists of a number of circuit modules or columns, each of which has local, excitatory and inhibitory connections as well as feedback connections. The columns interact with each other via the long-range horizontal connections. Besides these intrinsic connections, the pyramidal and spiny cells in the superficial layers receive the specific cue-related input and all the cortical neurons receive a hypothetical bias input. The model cortical circuit amplifies the response to the transient, cue-related input. The dynamics of the circuit evolves autonomously after the termination of the input. As a result, the circuit reaches in several hundred milliseconds an equilibrium state, in which the neurons exhibit graded-level, sustained activity. The sustained activity varies gradually with the cue direction, thus forming memory fields. In the formation of the memory fields, the feedback connections, the horizontal connections, and the bias input all play important roles. Varying the level of the bias input dramatically changes the dynamics of the model cortical neurons. The computer simulations show that there is an optimum level of the input for the formation of well-defined memory fields during the delay period.

This paper proposes an algorithm for analyzing the reachability property of Petri nets by the use of unfoldings. It is known that analyzing the reachability by using unfoldings requires exponential time and space to the size of unfolding. The algorithm is based on the branch and bound technique, and experimental results show efficiency of the algorithm.

This paper proposes a novel sequential coherent preambleless demodulator that uses phase signals instead of complex signals in the automatic frequency control (AFC) and carrier recovery circuits. The proposed demodulator employs a phase-combined frequency error detection circuit and dual loop AFC circuit to achieve fast frequency acquisition and low frequency jitter. It also adopts an open loop carrier recovery scheme with a sample hold circuit after the carrier filter to ensure carrier signal stability within a packet. It is shown that the frame error rate performance of the proposed demodulator is superior, by 30%, to that offered by differential detection in a frequency selective Rayleigh fading channel. The hardware size of the proposed demodulator is about only 1/10 that of a conventional coherent demodulator employing complex signals.

This paper is consisting of the two novel EMC technologies that we have been developed in our laboratory. The first is the technology for measuring the RF (Radio Frequency) nearby magnetic field and estimation of the RF current in the printed circuit board (PCB) by using the small loop antenna with multi-layer PCB structure developed by our laboratory. I introduce the application of our small loop antenna with its physical structure and the analysis of the nearby magnetic field distribution of the printed circuit board applying the discrete Wavelet analysis. We can understand the behavior of the digital circuit in detail, and we can also take measures to meet the specification about the electromagnetic radiation from the digital circuit from the higher order of priority by using these technologies. The second is our proposing novel technology for reducing the electromagnetic radiation from the digital equipment by taking notice of the improvement of the de-coupling in the PCB. We confirmed the remarkable effect of this technology by redesigning the motherboard of the small-sized computer.

Various I/O interface technologies in today's PC platform are classified into four categories, (1) ASIC (memory Controller) from / to Main Memory, (2) MPU from /to ASIC (Memory Controller), (3) ASIC (Memory Controller) from / to ASIC (Graphic Controller) and (4) ASIC from / to Peripherals. As to Category 1, effectiveness of SSTL is shown in DIMM application of SDRAM and DDR SDRAM over 100 MHz frequency. Furthermore a comparison is made between SLDRAM and D- RDRAM from the technology point of view. Concerning Categories 2 through 4, several interfaces such as PCI, AGP, GTL, HSTL and LVDS are reviewed. Interface technologies will keep playing an important role since computer systems require higher and higher speeds.

A novel method for the radiated immunity test is proposed. The method is to generate controlled electromagnetic fields applying in arbitrary directions to an under test. The fields rotate at a low speed controlled electrically so that the immunity characteristics may be known in more detail. The primal characteristics of the fields generated by a trial benchtop setup are investigated.

In Adleman's Function Field Sieve algorithm solving the discrete logarithm problem in a finite field, it is assumed that a random bivariate polynomial in the certain class is absolutely irreducible with high probability. In this letter we point out that if we use Cab type random polynomials then we always get absolutely irreducible polynomials. We can also simplify the calculation of a product of many rational functions on a curve that belongs to the field of definition by the use of a Cab curve.

Optoelectronic hybrid integration is a promising technology for realizing the optical components needed in optical transmission, switching, and interconnection systems that use wavelength division multiplexing (WDM) and time division multiplexing (TDM). We have already developed versatile optical hybrid integrated modules using a silica-based planar lightwave circuit (PLC) platform. However, these modules consist solely of the optoelectronic semiconductor devices such as laser diodes (LDs) and photo diodes (PDs) and monolithic optoelectronic integrated circuits (OEICs). To carry out high-speed and versatile electric signal processing functions in future network systems, it is necessary to install semiconductor electrical integrated circuits (ICs) on a PLC platform. In this paper, we describe novel technologies for high-speed PLC platforms which make it possible to assemble both ICs and optoelectronic devices. Using these technologies, we fabricated a two-channel hybrid integrated optical transmitter module which is hybrid integrated with an LD array chip and an LD driver IC. On this PLC platform, we use microstrip lines (MSLs) to drive the LD driver IC. We also considered the effect of heat interference on the LD array chip caused by the LD driver IC when designing the layout of the chip assembly region. The LD array chip and the LD driver IC were flip-chip bonded with solder bumps of a different material to avoid any deterioration in the coupling efficiency of the LD array chip. The optical transmitter module we fabricated operated successfully at 9 Gbit/s non-return-zero (NRZ) signal. This approach using a PLC platform for the hybrid integration of an LD array chip and an LD driver IC will carry forward the development of high-speed optoelectronic modules with both optical and electrical signal processing functions.

Optoelectronic hybrid integration is a promising technology for realizing the optical components needed in optical transmission, switching, and interconnection systems that use wavelength division multiplexing (WDM) and time division multiplexing (TDM). We have already developed versatile optical hybrid integrated modules using a silica-based planar lightwave circuit (PLC) platform. However, these modules consist solely of the optoelectronic semiconductor devices such as laser diodes (LDs) and photo diodes (PDs) and monolithic optoelectronic integrated circuits (OEICs). To carry out high-speed and versatile electric signal processing functions in future network systems, it is necessary to install semiconductor electrical integrated circuits (ICs) on a PLC platform. In this paper, we describe novel technologies for high-speed PLC platforms which make it possible to assemble both ICs and optoelectronic devices. Using these technologies, we fabricated a two-channel hybrid integrated optical transmitter module which is hybrid integrated with an LD array chip and an LD driver IC. On this PLC platform, we use microstrip lines (MSLs) to drive the LD driver IC. We also considered the effect of heat interference on the LD array chip caused by the LD driver IC when designing the layout of the chip assembly region. The LD array chip and the LD driver IC were flip-chip bonded with solder bumps of a different material to avoid any deterioration in the coupling efficiency of the LD array chip. The optical transmitter module we fabricated operated successfully at 9 Gbit/s non-return-zero (NRZ) signal. This approach using a PLC platform for the hybrid integration of an LD array chip and an LD driver IC will carry forward the development of high-speed optoelectronic modules with both optical and electrical signal processing functions.

A novel testing-pad placement method has been developed to greatly improve E-beam observability for multi-level wiring LSIs. In the method, testing pads connecting a lower-metal-layer wire with a top-metal-layer electrode are positioned in the design layout, making removal of the insulator unnecessary. The method features i) pad placement in unoccupied areas in mask patterns to avoid increases in chip size, ii) minimized pad size through the use of stacked vias so that the pads can be placed on as many wire nodes as possible, iii) placement as far as possible from the nearby wires to avoid local field effects, and iv) allocation of one testing pad to one circuit node to minimize the number of testing pads. These measures give us a practical pad-placement method, that has little influence on LSI design. It was shown that the proposed method yielded a dramatic improvement of observability from 13-33% to 88-99% in actual layouts of 0.25-µm ASICs with 20k, 120k, and 390k gates. It was also found that local field effects from nearby wires are negligible for almost all the testing pads. This approach will enable the use of E-beam testing on LSIs made with 0.25-µm technology and the even more sophisticated process technologies to come.

Connector contact resistance may become unstable if fretting occurs. Such motions result in the formation of insulating oxides on the surface of base metal contacts or organic polymers on contacts made of platinum group metals. These degradations are termed fretting corrosion and frictional polymerization, respectively. Motion may be caused by external vibration or fluctuating temperature. The lower the frequency of movement, the fewer the number of cycles to contact failure. Increasing the contact normal load or reducing the amplitude of movement may stabilize the connection. Tin and palladium and many of their alloys are especially prone to fretting failure. Tin mated to gold is worse than all-tin contacts. Gold and high gold-silver alloys that are softer when mated to palladium stabilize contact resistance since these metals transfer to the palladium during fretting; but flash gold coatings on palladium and palladium nickel offer marginal improvement for the gold often quickly wears out. Dissimilar metal contact pairs show behaviors like that of the metal which predominates on the surface by transfer. Contact lubricants can often prevent fretting failures and may even restore unlubricated failed contacts to satisfactory service.

Much of the data we deal with every day is organized hierarchically: file systems, library classification schemes and yellow page categories are salient examples. Business data too, benefits from a hierarchical organization, and indeed the hierarchical data model was quite prevalent thirty years ago. Due to the recently increased importance of X. 500/LDAP directories, which are hierarchical, and the prevalence of aggregation hierarchies in datacubes, there is now renewed interest in the hierarchical organization of data. In this paper, we develop a framework for a modern hierarchical data model, substantially improved from the original version by taking advantage of the lessons learned in the relational database context. We argue that this new hierarchical data model has many benefits with respect to the ubiquitous flat relational data model.

In order to exploit fully the frequency diversity benefits of multicarrier modulation (MCM), and the very nature of the frequency selective radio channel, we investigate an erasure decoded π/4 QDPSK MCM (ED-MCM) by employing simple Hamming (block) code. We propose the threshold-free criteria, i. e. relative minimum receive power test (RMRPT) and relative maximum decision error test (RMDET) for erasure generation and evaluate ED-MCM's performance by applying these tests to average received power, average decision error, instantaneous symbol/bit decision errors. At a normalized delay spread of 1/64, computer simulation results indicate a coding gains of 6.0 - 7.0 dB with ED-MCM at a BER of 10-3. RMDET/RMRPT based erasure decoding yields a 1.5 - 2.5 dB improvement over the conventional forward error correction (FEC) decoding at a BER of 10-5. The simulation results at other normalized delay spreads, i. e. , 1/32, 1/16 are also obtained. The erasure criteria (RMRPT and RMDET) applied to average values of received power/decision error yield consistently better performance over error only decoding. The results indicate that the erasure decoding based on relative (threshold-free) measures clearly promises an improved performance of the MCM system.

We study resource allocation strategies in ATM switches, which provide quality of service (QoS) guarantees to individual connections. In order to minimize the cell loss rate over a wide range of traffic characteristics, an efficient allocation strategy is necessary. In this paper we introduce a resource allocation strategy, named TP+WRR (Threshold Pushout + Weighted Round Robin) which can fully utilize the buffer space and the bandwidth. We compare the performance of TP+WRR with two typical resource allocation strategies. An exact queueing analysis based on a Markov model is carried out under bursty traffic sources to evaluate their performance. Our results reveal that TP+WRR considerably improves the cell loss probability over the other strategies considered in this paper, especially when many connections are sharing a link.

Although threshold key-recovery systems for the discrete log based cryptosystems such as the ElGamal scheme have been proposed by Feldman and Pedersen , no (practical) threshold key-recovery system for the factoring based cryptosystems such as the RSA scheme has been proposed. This paper proposes the first (practical) threshold key-recovery systems for the factoring based cryptosystems including the RSA and Rabin schemes. Almost all of the proposed systems are unconditionally secure, since the systems utilize unconditionally secure bit-commitment protocols and unconditionally secure VSS.

Contact resistance of nickel hardened gold electroplate (NiHG) deposited on nickel-underplated phosphor bronze disk coupons (substrate) after thermal aging was measured with a hard gold-plated beryllium copper alloy pin probe by means of a four-point probe technique, compared to that of cobalt-hardened gold electroplate (CoHG). Surface of NiHG plated coupons after aging was analyzed by X-ray photoelectron spectroscopy (XPS) to investigate the influence of the oxide film formation during thermal aging on contact resistance of NiHG electroplate, compared to that of CoHG. Initial contact resistance of the NiHG coupons was less than 10 mΩ at a contact forces more than 0.05 N, increased to 10 mΩ at a contact force of 0.05 N after 100 hours aging at 200. In contrast, contact resistance of the CoHG coupons progressively increased with increase in aging time, reached 1000 mΩ even at a contact force of 0.05 N after 52 hours aging. XPS analysis for the NiHG coupons demonstrated that nickel oxide film was formed on the NiHG surface in conformity with parabolic growth kinetics, as cobalt oxide film formed on CoHG surface. However, a thickness of the latter film was approximately 4-fold larger than that of former after 100 hours aging at 200. The small increase in contact resistance of NiHG coupons after aging suggested to be due to inhibitory of nickel oxide film growth on the surface. The cause of relatively low and steady contact resistance of NiHG during thermal aging was discussed.

The static fatigue parameters of plastic sleeves are determined by dynamic fatigue and destructive tests. The failure probability and lifetime of the plastic sleeve are estimated by using these parameters. No failure is expected for 20 years if the plastic sleeve is used in a normal atmosphere (23, 60%RH) and hot water (50).

We have proposed an algorithm to apply perfectly matched layer (PML) absorbing boundary condition to the noncubic cell time-domain method. The extended method has a merit of flexibility in truncating the computational domain by the use of a curvilinear PML. In this paper we apply a circular PML for computing the scattered fields of a dielectric cylinder or cylindrical shell of arbitrary cross section shape. Numerical results are presented to demonstrate the accuracy of this method.