We propose a novel technique for the estimation of device-parameters suitable for postfabrication performance compensation and adaptive delay testing, which are effective means to improve the yield and reliability of LSIs. The proposed technique is based on Bayes' theorem, in which the device-parameters of a chip, such as the threshold voltage of transistors, are estimated by current signatures obtained in a regular IDDQ testing framework. Neither additional circuit implementation nor additional measurement is required for the purpose of parameter estimation. Numerical experiments demonstrate that the proposed technique can achieve 10-mV accuracy in threshold voltage estimations.

This paper describes mobile backhaul optical access network designs for future cellular systems, in particular, for those systems that exploit coordinated multipoints (CoMP) transmission/reception techniques. Wavelength-division-multiplexing passive optical networks (WDM-PON) are primarily considered and two proposals to enhance mobile backhaul capability of WDM-PONs for CoMP are presented. One is physical X2 links that support dedicated low latency and high capacity data exchange between base stations (BSs). The other is multicasting in WDM-PONs. It effectively reduces data/control transmission time from central node to multiple BSs joining CoMP. Evaluation results verify that the proposed X2 links and the multicasting enable more BSs to join CoMP by enhancing the mobile backhaul capability, which results in improved service quality for users.

Congestion inherently occurs on the Internet due to traffic concentration on certain nodes or links of networks. The traffic concentration is caused by inefficient use of topological information of networks in existing routing protocols, which reduces to inefficient mapping between traffic demands and network resources. Actually, the route with minimum cost, i.e., number of hops, selected as a transmission route by existing routing protocols would pass through specific nodes with common topological characteristics that could contribute to a large improvement in minimizing the cost. However, this would result in traffic concentration on such specific nodes. Therefore, we propose a measure of the distance between two nodes that is suitable for reducing traffic concentration on specific nodes. To consider the topological characteristics of the congestion points of networks, we define node-to-node distance by using a generalized norm, p-norm, of a vector of which elements are degrees of intermediate nodes of the route. Simulation results show that both the maximum Stress Centrality (SC) and the coefficient of variation of the SC are minimized in some network topologies by selecting transmission routes based on the proposed measure of node-to-node distance.

This paper proposes a novel method for object tracking by combining local feature and global template-based methods. The proposed algorithm consists of two stages from coarse to fine. The first stage applies on-line classifiers to match the corresponding keypoints between the input frame and the reference frame. Thus a rough motion parameter can be estimated using RANSAC. The second stage employs kernel-based global representation in successive frames to refine the motion parameter. In addition, we use the kernel weight obtained during the second stage to guide the on-line learning process of the keypoints' description. Experimental results demonstrate the effectiveness of the proposed technique.

In this paper, we study a boomerang attack approach on MD4-based hash functions, and present a practical 4-sum distinguisher against the compression function of the full 5-pass HAVAL. Our approach is based on the previous work by Kim et al., which proposed the boomerang distinguisher on the encryption mode of MD4, MD5, and HAVAL in the related-key setting. Firstly, we prove that the differential path for 5-pass HAVAL used in the previous boomerang distinguisher contains a critical flaw and thus the attack cannot work. We then search for new differential paths. Finally, by using the new paths, we mount the distinguisher on the compression function of the full 5-pass HAVAL which generates a 4-sum quartet with a complexity of approximately 211 compression function computations. As far as we know, this is the first result on the full compression function of 5-pass HAVAL that can be computed in practice. We also point out that the 4-sum distinguisher can also be constructed for other MD4-based hash functions such as MD5, 3-pass HAVAL, and 4-pass HAVAL. Our attacks are implemented on a PC and we present a generated 4-sum quartet for each attack target.

Context awareness is one of the ultimate goals of ubiquitous computing, and spatial information plays an important role in building context awareness. In this paper, we propose a new interoperable spatial information model, which is based on ucode relation (ucR) and Place Identifier (PI), for realizing ubiquitous spatial infrastructure. In addition, we propose a design environment for spatial information database using our model. Our model is based on ucode and its relation. ucode is 128 bits number and the number itself has no meaning. Hence, it is difficult to manage the relation between ucodes without using a tool. Our design environment provides to describe connection between each ucode visually and is able to manipulate data using the target space map interactively. To evaluate the proposed model and environment, we designed three spaces using our tool. In addition, we developed a web application using our spatial model. From evaluation, we have been showed that our model is effective and our design environment is useful to develop our spatial information model.

We propose a new analytical method for a composite dielectric grating embedded with conducting strips using scattering factors in the shadow theory. The scattering factor in the shadow theory plays an important role instead of the conventional diffraction amplitude. By specifying the relation between scattering factors and spectral-domain Green's functions, we derive expressions of the Green's functions directly for unit surface electric and magnetic current densities, and apply the spectral Galerkin method to our formulation. From some numerical results, we show that the expressions of the Green's functions are valid, and analyze scattering characteristics by composite gratings.

This paper discusses hybrid state saving for applications in which processes should create checkpoints at constant intervals and can hold a finite number of checkpoints. We propose a reclamation technique for checkpoint space, that provides effective checkpoint time arrangements for a rollback distance distribution. Numerical examples show that when we cannot use the optimal checkpoint interval due to the system requirements, the proposed technique can achieve lower expected overhead compared to the conventional technique without considering the form of the rollback distance distribution.

In this paper we propose MR-MAC, a new multiple reservation MAC protocol for asynchronous duty cycling wireless sensor networks. In MR-MAC, the receiver transmits a collection packet to the senders when it wakes up that asks for the number of packets each sender wants to send. Then each sender replies to the receiver according to the scheduled sequence with a short report packet. After getting the number of packets from each sender, the receiver assigns multiple batch transmission (MBT) for the senders and begins to initiate the transmissions. The senders then transmit packets to the receiver in a batch style as scheduled so that packets can be delivered to the receiver as fast as possible. Experiments on a Tmote-sky testbed show that our protocol outperforms other protocols in diverse performance metrics such as throughput, latency and energy efficiency.

Network slicing for wide-area coordinated packet processing has attracted attentions for improving efficiency of handling network traffic. We have recently proposed a tag-based network slicing mechanism called OpenTag, and introduced the prototype implementation of the OpenTag redirector on an evaluation board. In this paper, we investigate the integration of the OpenTag redirector into a commercial network device. Our contributions are three-fold: (1) designing the architecture aiming OpenTag-capable intermediaries embedded on commercial network devices, (2) implementing a prototype of the embedded OpenTag redirector using the Advanced Mezzanine Card (AMC) which has an OCTEON network processor, (3) showing our implementation can tolerate high bandwidth environment.

An important factor determining the performance of delay tolerant networks (DTNs) is packet delivery delay. In this paper, we study the block delivery delay of DTN with the epidemic routing scheme based on random linear network coding (RLNC). First, simulations show that the influence of relay buffer size on the delivery delay is not as strong in RLNC-based routing as it is in replica-based routing. With this observation,we can simplify the performance analysis by constraining the buffer of the relay node to just one size. Then we derive the cumulative distribution function (CDF) of block delivery delay with difference equations. Finally, we validate the correctness of our analytical results by simulations.

In this paper, we propose a geographic location-based distributed routing (GDR) system. The GDR system provides information lookup based on latitude and longitude coordinates. Each node of the GDR system utilizes the coordinates as an identifier (ID), and manages an overlay routing table. An ID is generated to reflect the geographical location without using Space Filling Curve (SFC). The ID is in cartesian format (x, y), which represents the longitude x and latitude y. In a system with N nodes, each node has a routing table of size log N and a search is possible in O(log N). We evaluate the routing performance of GDR and other systems based on Chord, Kademlia and CAN. We show that in both the ID is in cartesian format and the ID is generated by using SFC, GDR, Chord and Kademlia have the same mean and the same variance of the path length, while the mean and the variance of the relay length of GDR are smaller than those of Chord and Kademlia. Furthermore, while GDR and CAN have the same mean and the same variance of the relay length, the mean and the variance of the path length of GDR are smaller than those of CAN.

In the theory of diffraction gratings, the conventional integral method is considered as a powerful tool of numerical analysis. But it fails to work at a critical angle of incidence, because a periodic Green's function (integral kernel) diverges. This problem was resolved by the image integral equation in a previous paper. Newly introducing the reflection extinction theorem, this paper derives the image extinction theorem and the image integral equation. Then, it is concluded that the image integral equation is made up of two physical processes: the image surface radiates a reflected plane wave, whereas the periodic surface radiates the diffracted wave.

A method of calibration for GPR responses is introduced in order to extract a target response from GPR data. This calibration procedure eliminates undesirable waveform distortion that is caused by antenna characteristics and multiple scattering effects between the antennas and the ground surface. An application result to measured GPR data shows that undesirable late-time responses caused by the antenna characteristics and multiple scattering effects are removed, and that the target response is clearly reconstructed. This result demonstrates that the waveform calibration of GPR data is significant and essential for reliable target identification.

In this paper, to provide scalability and mobility of sinks and events, we propose a new independent structure-based routing protocol which exploits a k-level Independent Grid Structure (IGS) for data dissemination from sources to sinks. Beside the k-level IGS, the proposed protocol does not to construct any additional routing structure irrespective of the number and the movement of both sinks and events. The proposed protocol also allows query or report packets to be sent to only a few grid headers in the k-level IGS and provides aggregation and multicasting of report packets by the k-level IGS. Simulation results show that the proposed protocol is superior to other protocols regarding to energy-efficiency.

This paper presents an alternative approach for the analysis of EM field by a rotating body with FDTD method and Overset Grid Generation method, considering Lorentz transformation for the higher velocity cases. This approach has been previously proposed for the case of linear and uniformly moving body against/to the incident wave. Here, the approach is expanded to a rotating body which includes the interpolation technique in the space and time increment along the cylindrical rotation at the fixed axis. First, the grid size ratios between the main mesh and the sub-mesh are studied. The appropriate choice of the grid size ratio is obtained. Then, the modulations of the EM field when the incident wave hits the rotating body in high velocity cases are analyzed. The relationship of the phase shift and the velocity is further observed. The observed EM fields are compared with the theoretical results and achieved good agreements in high relative velocities. The assessment of the numerical errors in a rotating environment is also highlighted. This numerical approach may have numerous situations to which it can be applied. This may be involved with the design of rotating devices such as microactuator, commutator and others.

This paper shows a known-key distinguisher on the internal block cipher of tweaked Lesamnta reduced to 31 (out of 32) rounds, which is one of the hash functions submitted to the SHA-3 competition. Moreover, the paper presents a distinguisher for full internal block cipher of Lesamnta with stronger assumption. For its tweaked version, all previous cryptanalysis can work no more than 24 rounds. We search for a new integral characteristic for the internal block cipher, and discover a 19-round integral characteristic for forward direction. We then search for an integral characteristic for backward direction, and the characteristics can be combined to full rounds with some assumption. The distinguisher for the internal block cipher of Lesamnta-256 requires 2192 query complexity and negligible memory. This is the best attack on Lesamnta compression function and its internal block cipher after the tweak.

Finding DC operating points of nonlinear circuits is an important and difficult task. The Newton-Raphson method adopted in the SPICE-like simulators often fails to converge to a solution. To overcome this convergence problem, homotopy methods have been studied from various viewpoints. However, most previous studies are mainly focused on the bipolar transistor circuits and no paper presents the global convergence theorems of homotopy methods for MOS transistor circuits. Moreover, due to the improvements and advantages of MOS transistor technologies, extending the homotopy methods to MOS transistor circuits becomes more and more necessary and important. This paper proposes two nonlinear homotopy methods for MOS transistor circuits and proves the global convergence theorems for the proposed MOS nonlinear homotopy method II. Numerical examples show that both of the two proposed homotopy methods for MOS transistor circuits are more effective for finding DC operating points than the conventional MOS homotopy method and they are also capable of finding DC operating points for large-scale circuits.

This paper investigates power gating implementations that mitigate power supply noise. We focus on the body connection of power-gated circuits, and examine the amount of power supply noise induced by power-on rush current and the contribution of a power-gated circuit as a decoupling capacitance during the sleep mode. To figure out the best implementation, we designed and fabricated a test chip in 65 nm process. Experimental results with measurement and simulation reveal that the power-gated circuit with body-tied structure in triple-well is the best implementation from the following three points; power supply noise due to rush current, the contribution of decoupling capacitance during the sleep mode and the leakage reduction thanks to power gating.

In this paper we report on an approach inspired by Ant Colony Optimization (ACO) to provide a fault tolerant and efficient means of transferring data in dynamic environments. We investigate the problem of distributing data between a client and server by using pheromone equations. Ants choose the best source of food by selecting the strongest pheromone trail leaving the nest. The pheromone decays over-time and needs to be continually reinforced to define the optimum route in a dynamic environment. This resembles the dynamic environment for the distribution of data between clients and servers. Our approach uses readily available network and server information to construct a pheromone that determines the best server from which to download data. We demonstrate that the approach is self-optimizing and capable of adapting to dynamic changes in the environment.