A scan chain is one of the most important testing techniques, but it can be used as side-channel attacks against a cryptography LSI. We focus on scan-based attacks, in which scan chains are targeted for side-channel attacks. The conventional scan-based attacks only consider the scan chain composed of only the registers in a cryptography circuit. However, a cryptography LSI usually uses many circuits such as memories, micro processors and other circuits. This means that the conventional attacks cannot be applied to the practical scan chain composed of various types of registers. In this paper, a scan-based attack which enables to decipher the secret key in an AES cryptography LSI composed of an AES circuit and other circuits is proposed. By focusing on bit pattern of the specific register and monitoring its change, our scan-based attack eliminates the influence of registers included in other circuits than AES. Our attack does not depend on scan chain architecture, and it can decipher practical AES cryptography LSIs.

We consider a problem of global asymptotic stabilization of a class of feedforward nonlinear systems that have the unknown linear growth rate and unknown input delay. The proposed output feedback controller employs a dynamic gain which is tuned adaptively by monitoring the output value. As a result, a priori knowledge on the linear growth rate and delay size are not required in controller design, which is a clear benefit over the existing results.

The need for data encryption that protects sensitive data in a database has increased rapidly. However, encrypted data can no longer be efficiently queried because nearly all of the data should be decrypted. Several order-preserving encryption schemes that enable indexes to be built over encrypted data have been suggested to solve this problem. They allow any comparison operation to be directly applied to encrypted data. However, one of the main disadvantages of these schemes is that they expose sensitive data to inference attacks with order information, especially when the data are used together with unencrypted columns in the database. In this study, a new order-preserving encryption scheme that provides secure queries by hiding the order is introduced. Moreover, it provides efficient queries because any user who has the encryption key knows the order. The proposed scheme is designed to be efficient and secure in such an environment. Thus, it is possible to encrypt only sensitive data while leaving other data unencrypted. The encryption is not only robust against order exposure, but also shows high performance for any query over encrypted data. In addition, the proposed scheme provides strong updates without assumptions of the distribution of plaintext. This allows it to be integrated easily with the existing database system.

Higher-order rewrite systems (HRSs) and simply-typed term rewriting systems (STRSs) are computational models of functional programs. We recently proposed an extremely powerful method, the static dependency pair method, which is based on the notion of strong computability, in order to prove termination in STRSs. In this paper, we extend the method to HRSs. Since HRSs include λ-abstraction but STRSs do not, we restructure the static dependency pair method to allow λ-abstraction, and show that the static dependency pair method also works well on HRSs without new restrictions.

In 1999, Gennaro, Halevi and Rabin proposed a signature which achieves provable security without assuming the random oracles, and it is the first RSA-type signature whose security is proved in the standard model. Since that time, several signatures have been proposed to achieve better efficiency or useful property along with the provable security in the standard model. In this paper, we construct a trapdoor hash function, and design an efficient online/offline signature by using the trapdoor hash function. Our signature scheme requires only one non-modular multiplication of two small integers for online signing, and it provides the fastest online signing among all online/offline signatures that achieve provable security in the standard model.

To realize huge-scale information services, many Distributed Hash Table (DHT) based systems have been proposed. For example, there are some proposals to manage item-level product traceability information with DHTs. In such an application, each entry of a huge number of item-level IDs need to be available on a DHT. To ensure data availability, the soft-state approach has been employed in previous works. However, this does not scale well against the number of entries on a DHT. As we expect 1010 products in the traceability case, the soft-state approach is unacceptable. In this paper, we propose Distributed-to-Distributed Data Copy (D3C). With D3C, users can reconstruct the data as they detect data loss, or even migrate to another DHT system. We show why it scales well against the number of entries on a DHT. We have confirmed our approach with a prototype. Evaluation shows our approach fits well on a DHT with a low rate of failure and a huge number of data entries.

In this paper, we analyze the stability of XCP (eXplicit Control Protocol) in a network with heterogeneous XCP flows (i.e., XCP flows with different propagation delays). Specifically, we model a network with heterogeneous XCP flows using fluid-flow approximation. We then derive the conditions that XCP control parameters should satisfy for stable XCP operation. Furthermore, through several numerical examples and simulation results, we quantitatively investigate effect of system parameters and XCP control parameters on stability of the XCP protocol. Our findings include: (1) when XCP flows are heterogeneous, XCP operates more stably than the case when XCP flows are homogeneous, (2) conversely, when variation in propagation delays of XCP flows is large, operation of XCP becomes unstable, and (3) the output link bandwidth of an XCP router is independent of stability of the XCP protocol.

This paper proposes a power saving control function for battery-powered portable wireless LAN (WLAN) access points (APs) to extend the battery life. The IEEE802.11 standard does not support power saving control for APs. To enable a sleep state for an AP, the AP forces the stations (STAs) to refrain from transmitting frames using the network allocation vector (NAV) while the AP is sleeping. Thus the sleep state for the AP can be employed without causing frame loss at the STAs. Numerical analysis and computer simulation reveal that the newly proposed control technique conserves power compared to the conventional control.

The purpose of this paper is to investigate the possible impact of cellular phones' signals on implantable cardiac pacemakers in elevators. This is achieved by carrying out precise numerical simulations based on the Finite-Difference-Time-Domain method to examine the electromagnetic fields in elevator models. In order to examine the realistic and complicated situations where humans are present in the elevator, we apply the realistic homogeneous human phantom and cellular radios operating in the frequency bands 800 MHz, 1.5 GHz and 2 GHz. These computed results of field strength inside the elevator are compared with a certain reference level determined from the experimentally obtained maximum interference distance of implantable cardiac pacemakers. This enables us to carry out a quantitative evaluation of the EMI risk to pacemakers by cellular radio transmission. The results show that for the case when up to 5 mobile radio users are present in the elevator model used, there is no likelihood of pacemaker malfunction for the frequency bands 800 MHz, 1.5 GHz and 2 GHz.

The importance of redundant technologies for improving dependability and delay fault testability are growing. This paper presents properties of a class of redundant technologies, namely two-rail logic, and analyzes testability of path delay faults occurring on two-rail logic circuits. The paper reveals the following characteristics of two-rail logic circuits: While the number of paths in two-rail logic circuits is twice that in ordinary single-rail logic circuits, the number of robust testable path delay faults in two-rail logic circuits is twice or more that in the single-rail logic circuits. This suggests two-rail logic circuits are more testable than ordinary single-rail logic circuits. On two-rail logic circuits, there may be some robust testable path delay faults that are functional un-sensitizable for any input vectors consisting of codewords of two-rail codes, i.e. for any input vectors that can occur during fault-free operation. Even if such faults occur, the circuits are still strongly fault secure for unidirectional stuck-at faults as well as they work correctly.

In this letter we give a lower bound on the worst-case time complexity of Dijkstra's three-state mutual exclusion algorithm by specifying a concrete behavior of the algorithm. We also show that our result is more accurate than the known best bound.

This study analyzes the absolute stability in P and PD type fuzzy logic control systems with both certain and uncertain linear plants. Stability analysis includes the reference input, actuator gain and interval plant parameters. For certain linear plants, the stability (i.e. the stable equilibriums of error) in P and PD types is analyzed with the Popov or linearization methods under various reference inputs and actuator gains. The steady state errors of fuzzy control systems are also addressed in the parameter plane. The parametric robust Popov criterion for parametric absolute stability based on Lur'e systems is also applied to the stability analysis of P type fuzzy control systems with uncertain plants. The PD type fuzzy logic controller in our approach is a single-input fuzzy logic controller and is transformed into the P type for analysis. In our work, the absolute stability analysis of fuzzy control systems is given with respect to a non-zero reference input and an uncertain linear plant with the parametric robust Popov criterion unlike previous works. Moreover, a fuzzy current controlled RC circuit is designed with PSPICE models. Both numerical and PSPICE simulations are provided to verify the analytical results. Furthermore, the oscillation mechanism in fuzzy control systems is specified with various equilibrium points of view in the simulation example. Finally, the comparisons are also given to show the effectiveness of the analysis method.

In this letter, we propose an efficient method to improve the performance of voiced/unvoiced (V/UV) sounds decision for the selectable mode vocoder (SMV) of 3GPP2 using the Gaussian mixture model (GMM). We first present an effective analysis of the features and the classification method adopted in the SMV. And feature vectors which are applied to the GMM are then selected from relevant parameters of the SMV for the efficient V/UV classification. The performance of the proposed algorithm are evaluated under various conditions and yield better results compared to the conventional method of the SMV.

A 0.18 µm 1.5 V/50 mA stability-enhanced low dropout regulator (LDO) is presented. A multi-path error amplifier and a split pass device structure are utilized for pole-zero pair compensation. The proposed LDO can be stable without a load capacitor and also stable with different combinations of load capacitors and equivalent series resistance.

This paper presents a grouped scan slice encoding technique using scan slice repetition to simultaneously reduce test data volume and test application time. Using this method, many scan slices that would be incompatible with the conventional selective scan slice method can be encoded as compatible scan slices. Experiments were performed with ISCAS'89 and ITC'99 benchmark circuits, and results show the effectiveness of the proposed method.

A multiple stream join is one of the most important but high cost operations in ubiquitous streaming services. In this paper, we propose a newly improved and practical algorithm for joining multiple streams called AMJoin, which improves the multiple join performance by guaranteeing the detection of join failures in constant time. To achieve this goal, we first design a new data structure called BiHT (Bit-vector Hash Table) and present the overall behavior of AMJoin in detail. In addition, we show various experimental results and their analyses for clarifying its efficiency and practicability.

In this letter, an acoustic environment classification algorithm based on the 3GPP2 selectable mode vocoder (SMV) is proposed for context-aware mobile phones. Classification of the acoustic environment is performed based on a Gaussian mixture model (GMM) using coding parameters of the SMV extracted directly from the encoding process of the acoustic input data in the mobile phone. Experimental results show that the proposed environment classification algorithm provides superior performance over a conventional method in various acoustic environments.

Optical buffer memory for 10-Gb/s data signal is demonstrated experimentally using a polarization bistable vertical-cavity surface-emitting laser (VCSEL). The optical buffer memory is based on an optical AND gate function and the polarization bistability of the VCSEL. Fast AND gate operation responsive to 50-ps-width optical pulses is achieved experimentally by increasing the detuning frequency between an injection light into the VCSEL and a lasing light from the VCSEL. A specified bit is extracted from the 10-Gb/s data signal by the fast AND gate operation and is stored as the polarization state of the VCSEL by the polarization bistability. The corresponding numerical simulations are also performed using two-mode rate equations taking into account the detuning frequency. The simulation results confirm the fast AND gate operation by increasing the detuning frequency as well as the experimental results.

In this letter, we consider a problem of global stabilization of a class of approximately feedback linearized systems. We propose a new nonlinear control approach which includes a nonlinear controller and a Lyapunov-based design method. Our new nonlinear control approach broadens the class of systems under consideration over the existing results.

Negative bias temperature instability (NBTI) has become a critical reliability phenomena in advanced CMOS technology. In this paper, we propose an analytical temperature-aware dynamic NBTI model, which can be used in two circuit operation cases: executing tasks with different temperatures, and switching between active and standby mode. A PMOS Vth degradation model and a digital circuits' temporal performance degradation estimation method are developed based on our NBTI model. The simulation results show that: 1) the execution of a low temperature task can decrease ΔVth due to NBTI by 24.5%; 2) switching to standby mode can decrease ΔVth by 52.3%; 3) for ISCAS85 benchmark circuits, the delay degradation can decrease significantly if the circuit execute low temperature task or switch to standby mode; 4) we have also observed the execution time's ratio of different tasks and the ratio of active to standby time both have a considerable impact on NBTI effect.