In the move toward higher clock rates and advanced process technologies, designers of the latest electronic products are finding increasing silicon failure with respect to noise. On the other hand, the minimum dimension of patterns on LSIs is much smaller than the wavelength of exposure, making it difficult for LSI manufacturers to obtain high yield. In this paper, we present a solution to reduce power-supply noise in LSI microchips. The proposed design methodology also considers design for manufacturability (DFM) at the same time as power integrity. The method was successfully applied to the design of a system-on-chip (SOC), achieving a 13.1-13.2% noise reduction in power-supply voltage and uniformity of pattern density for chemical mechanical polishing (CMP).

A novel scheme for a multi-band power amplifier (PA) that employs a low-loss reconfigurable matching network is presented and discussed. The matching network basically consists of a cascade of single-stub tuning circuits, in which each stub is connected to a transmission line via a Single-Pole-Single-Throw (SPST) switch. By controlling the on/off status of each switch, the matching network works as a band-switchable matching network. Based on a detailed analysis of the influence of non-ideal switches in the matching network, we conceived a new design perspective for the reconfigurable matching network that achieves low loss. A 900/1900-MHz dual-band, 1 W class PA is newly designed following the new design perspective, and fabricated with microelectro mechanical system (MEMS) SPST switches. Owing to the new design and sufficient characteristics of the MEMS switches, the dual-band PA achieves over 60% of the maximum power-added efficiency with an output power for each band exceeding 30 dBm. These results are comparable to the estimated results for a single-band PA. This shows that the proposed scheme provides a band-switchable highly efficient PA that has superior performance compared to the conventional multi-band PA that has a complex structure.

In this letter, we propose an enhanced gentle distributed coordination function (GDCF), which is a simple and effective collision resolution mechanism, to improve the performance of IEEE 802.11 DCF. We compare performance of the enhanced GDCF with that of the legacy DCF and the conventional GDCF via analysis and simulations. The enhanced GDCF introduces a new counter to check the number of consecutively successful transmissions, and the maximum permitted values of the counter differ for different backoff stages. The proposed GDCF is shown to have performance superior to that of the conventional GDCF for various combinations of contending stations and frame length.

TCP performance in the IEEE 802.11-based multihop ad hoc networks is extremely poor, because the congestion control mechanism of TCP cannot effectively deal with the problem of packet drops caused by mobility and shared channel contention among wireless nodes. In this paper, we present a cross-layer method, which adaptively adjusts the TCP maximum window size according to the number of RTS (Request To Send) retry counts of the MAC layer at the TCP sender, to control the number of TCP packets in the network and thus decrease the channel contention. Our simulation results show that this method can remarkably improve TCP throughput and its stability.

Modern telecom and signal relays have been optimized to carry and switch low signals and to withstand high dielectric strength. Recent designs have extremely small physical dimensions and are comparatively cheap. Small size and low cost also make this type of relay very attractive for industrial and automotive applications. For industrial and automotive applications performance characteristics other than low and stable contact resistance values are of importance. While, for industrial applications, safety aspects and inductive load switching characteristics are of major importance, in automotive applications, high switching currents, inductive and lamp loads and high ambient temperatures are essential. Tests were carried out in order to determine the limitations of small size relays. The results obtained clearly show the unexpectedly high load range which signal relays are able to cover. Despite their small size, these relays can handle switching loads up to several hundred volts and currents up to 5 A. On top of the high switching current there is high excess current capability, and relays can work at extreme ambient temperatures between -55 and more than +105 degrees C.

Ad hoc networks have recently become a hot topic. In ad hoc networks, battery power is an important resource, since most terminals are battery powered. Terminals consume extra energy when their network interfaces are in the idle state or when they overhear packets not destined for them. They should, therefore, switch off their radio when they do not have to send or receive packets. IEEE802.11 features a power saving mechanism (PSM) in Distributed Coordination Function(DCF). In PSM for DCF, nodes must stay awake for a fixed time, called ATIM window (Ad-Hoc Traffic Indication Map window). If nodes do not have data to send or receive, they enter the doze state except for during ATIM window. However, ad hoc networks with PSM have longer end-to-end delays to deliver packets and suffer lower throughput than the standard IEEE802.11. To solve this problem, this paper proposes a protocol that reduces delay and achieves high throughput and energy efficiency. Simulation results show that our proposal outperforms other PSMs in terms of throughput, end-to-end delay and energy efficiency.

Photonic crystal fiber (PCF) is a promising candidate for future transmission media due to its unobtainable features in a conventional single-mode fiber. We discuss some important problems to realize a PCF for transmission purpose. We also present recent progress on the PCF as a transmission media.

A novel threshold choosing method for the threshold-based skip mechanism is presented, in which the threshold is obtained from the analysis of the video device induced noise variance. Simulation results show that the proposed method can remarkably reduce the computation time consumption with only marginal performance penalty.

This paper presents an attempt to make rational active adversary passive using mechanism design. We propose a secure Generalized Vickrey Auction (GVA) scheme where the procedure executed by a bidder affects neither the prices nor the allocation of the bidder. Therefore, a bidder does not have an incentive to be an active adversary.

Various effective and draft legislations and rules in Europe (WEEE--Waste Electrical and Electronic Equipment ROHS--Restrictions on the use of certain substances and ELV--End of life of vehicles) and Japan (Recycling Law for Home Electric Appliances) have either targeted restrictions or fully banned on the use of lead, to be enforced from 2001, 2003 and 2006 onwards. Up to now, mainly tin-lead alloys have been used in electronics. The process temperatures usually applied have been in the range of 230. All currently discussed lead-free alternatives for professional electronics need process temperatures which are at least 20 higher. In addition, the process duration is significantly longer. The combination of higher process temperatures and longer duration results in significant thermal stress on electromechanical devices. In particular the precision mechanics of electromechanical relays must withstand the solder process with maximum process temperatures of 255 without dimensional changes. During the transition from tin-lead to lead-free solder processes all combinations of component surfaces and solder must be possible. The selection of pure Sn100 or SnCu0.7 as terminal surface allows mixed assemblies with tin-lead as well as lead-free solders. All tested combinations of terminal surface, PCB surface and solder showed good results. From these results it can be concluded that mixed assemblies are possible during the transition time without any negative impact on the reliability of the electronic devices.

In the emerging networks, routing may be performed at various levels of the TCP/IP stack, such as datagram, TCP stream or application level, with possibly different message forwarding modes. We formulate an abstract quickest path problem for the transmission of a message of size σ from a source to a destination with the minimum end-to-end delay over a network with bandwidth and delay constraints on the links. We consider six modes for the message forwarding at the nodes reflecting the mechanisms such as circuit switching, store and forward, and their combinations. For each of first five modes, we present O( m2 + mn log n ) time algorithms to compute the quickest path for a given message size σ. For the last mode, the quickest path can be computed in O(m + n log n ) time.

Classical studies of Asynchronous Transfer Mode (ATM) switching elements and in particular the buffer behavior of the Shared Buffer Memory (SBM), assume that all read and write operations of cells to, respectively from, the SBM are executed simultaneously. However, in a real switching element, the inlets (outlets) are scanned sequentially for arriving (departing) cells during the so-called input (output) cycle. Furthermore, the input and output cycles are intermingled, each read operation being followed by a write operation. This is referred to as the Timeslot Interchange Mechanism (TIM). In this paper, we present the analysis of a queueing model that includes the TIM. We model the cell arrival processes on the inlets of the switching element as independent Bernoulli arrival processes. Moreover, we assume that cells are routed from the inlets to the outlets of the switching element according to an independent and uniform process, i.e., the destinations of consecutive cell arrivals on any given inlet are independent and for a given cell all destinations are equiprobable. Under these assumptions, we will derive expressions for the probability generating functions of the queue length in an individual routing group (a logical queue that contains all cells scheduled for the same destination), the (total) queue length in the SBM, and the cell waiting time. From these results, expressions for the mean values and the tail distributions of these quantities are calculated, and the influence of the TIM on the buffer behavior is studied through comparison with a model where all read and write operations occur simultaneously.

We discuss photonic crystals (PhCs) with advanced micro/nano-structres which are semiconductor quantum dots (QDs) and micro electro-mechanical systems (MEMS) for the purpose of realizing novel classes of PhC devices in future photonic network system. After brief introduction on advantages to implement QDs and MEMS with PhCs, we discuss optical characterization of PhC microcavity containing self-assembled InAs QDs. Modification of emission spectrum of a QD ensemble due to the resonant cavity modes is demonstrated. We also point out the feasibility of low-threshold PhC lasers with QD active media in numerical analysis. A very low threshold current of 10 µA is numerically obtained for lasing action in the multi dimensional distributed feedback mode by using realistic material parameters. Then, the basic concept for MEMS-controlled PhC slab devices is described. We show numerical results that demonstrate some of interesting functions such as the intensity modulation and the tuning of resonant frequency of cavity mode. Finally, a preliminary experiment of MEMS-based switching operation in a PhC line-defect waveguide is demonstrated.

In this paper, we propose a preemptive test scheduling technique (a test can be interrupted and later resumed) for core-based systems with the objective to minimize the test application time. We make use of reconfigurable core test wrappers in order to increase the flexibility in the scheduling process. The advantage with such a wrapper is that it is not limited to a single TAM (test access mechanism) bandwidth (wrapper chain configuration) at each core. We model the scheduling problem as a Bin-packing problem, and we discuss the transformation: number of TAM wires (wrapper-chains) versus test time in combination with preemption, as well as the possibilities and the limitations to achieve an optimal solution in respect to test application time. We have implemented the proposed preemptive test scheduling algorithm, and we have through experiments demonstrated its efficiency.

This paper proposes an SoC test architecture generation framework. It contains a database, which stores the test cost information of several DFTs for every core, and a DFT selection part which performs DFT selection for minimizing the test application time using this database in the early phase of the design flow. Moreover, the DFT selection problem is formulated and the algorithm that solves this problem is proposed. Experimental results show that bottlenecks in test application time when using a single DFT method for all cores in an SoC is reduced by performing DFT selection from two types of DFTs. As a result, the whole test application time is drastically shortened.

A mechanical phase shifter is designed for beam scanning in co-phase fed single-layer slotted waveguide arrays. The multiple-way power divider in this array consists of a series of π-junctions with one guide wavelength spacing in a feed waveguide. The movable narrow walls placed between the π-junctions perturb the guide wavelength as well as the phase of output ports. Method of Moment (MoM) analysis for one unit consisting of one movable plate and two junctions is conducted to estimate the available phase shift as well as the degradation of reflection. A phase shift of 86 degrees is predicted between two π-junctions under the condition of reflection below -20 dB; experiments at 4 GHz confirmed the design. The beam scanning capability of the arrays is also surveyed and the beam-scanning of about 10 degrees is predicted.

We show a geometric method to compute the Van der Waals factor 1/r7 between the assemblies of amino acid molecules of the subunits of acetyl choline (abbreviated by Ach: a kind of neuro chemical transmitter) sensitive channel on the post synaptic membrane of the neural system. We induced a analytical geometric formula for the distances between helically arranged ten assemblies of the point amino acid molecules on two interacting membrane perforating poly peptides, M2 helices during channel opening deformation. Detailed geometric parameters have been utilized from reported biophysical measurements. The computed Van der Waals factor decreased rapidly as the slope of the first M2 helix along the central axis of the channel pore has increased. The Van der Waals factor also decreased by an increase in rising angle of the helically arranged amino acids on the M2 helices. The Van der Waals factor increased significantly as the first M2 helix has rotated around the central axis of the channel pore to take an opening position. We discussed the time dependent molecular structural changes of the Ach sensitive channel opening in conjunction with the Allosteric properties of the bio molecules. The molecular mechanism of Ach sensitive channel opening in terms of the Allosteric property may derive from the characteristic helical constitutional nature of the membrane perforating part (M2 helix) of the subunits of the channel molecule.

This paper presents a refined model for the fuzzy logic implementation of an available bit rate (ABR) flow control switch. This refined model is named fuzzy explicit rate (FUER) switch mechanism. FUER switch mechanism is designed to effectively perform congestion control on ABR traffic in asynchronous transfer mode (ATM) networks. The performance of FUER scheme is evaluated against those of two other explicit rate (ER)-based switch mechanisms using simulation in particular local area network (LAN) and wide area network (WAN) environments. On the whole, FUER scheme performs better than the other schemes. Although it has the smallest control parameter set, it is a more efficient and scalable ER-based switch mechanism.

A new rewritable medium utilizing a guest-host (G-H) polymer-dispersed liquid-crystal (PDLC) film has been developed in our laboratory. The medium is thermally written and electrically erased. It is portable, like paper, and can store recorded data because of the memory effect of smectic-A liquid crystal (SmA LC), which exhibits bistable states of homeotropic and focal conic alignment. Dichroic dye is added to the SmA LC to form the G-H type. An evaluation of the characteristics revealed that this medium exhibits both high contrast and good reliability.

In computer-aided drafting and design, interactive graphics is used to design components, systems, layouts, and structures. There are several approaches for using automated graphical layout tools currently. Our approach employs a genetic algorithm to implement a tool for automated 3D graphical layout design and presentation. The effective use of a genetic algorithm in automated graphical layout design relies on defining a fitness function that reflects user preferences. In this paper, we describe a method to define fitness functions and chromosome structures of selected objects. A learning mechanism is employed to adjust the fitness values of the objects in the selected layout chosen by the user. In our approach, the fitness functions can be changed adaptively reflecting user preferences. Experimental results revealed good performance of the adaptive fitness functions in our proposed mechanism.