Since scan testing is not based on the function of the circuit, but rather the structure, it is considered to be both a form of over testing and under testing. Moreover, it is important to test VLSIs using the given function. Since the functional specifications are described explicitly in the FSMs, high test quality is expected by performing logical fault testing and timing fault testing. This paper proposes a fault-dependent test generation method to detect specified fault models completely and to increase defect coverage as much as possible under the test length constraint. We present experimental results for MCNC'91 benchmark circuits to evaluate bridging fault coverage, transition fault coverage, and statistical delay quality level and to show the effectiveness of the proposed test generation method compared with a stuck-at fault-dependent test generation method.

This paper presents an intuitive interaction technique for data exchange between multiple co-located devices. In the proposed system, CrossOverlayDesktop, desktop graphics of the devices are graphically overlaid with each other (i.e., alpha-blended). Users can exchange file data by the usual drag-and-drop manipulation through an overlaid area. The overlaid area is determined by the physical six degrees of freedom (6-DOF) correlation of the devices and thus changes according to users' direct movements of the devices. Because familiar operations such as drag-and-drop can be applied to file exchange between multiple devices, seamless, consistent, and thus intuitive multi-user collaboration is realized. Furthermore, dynamic overlay of desktop graphics allows users to intuitively establish communication, identify connected devices, and perform access control. For access control of the data, users can protect their own data by simply dragging them out of the overlaid area, because only the overlaid area becomes a public space. Several proof-of-concept experiments and evaluations were conducted. Results show the effectiveness of the proposed interaction technique.

Geographic routing for wireless sensor networks requires a source that can encapsulate the location of a sink in each data packet. How a source can obtain the location of a sink with low overhead is a difficult issue. This letter proposes a Quorum Based Sink Location Service (QSLS) which can be exploited by most geographic routing protocols in arbitrary irregular wireless sensor networks.

A three-dimensional semiconductor package structure with inter-chip connections was developed for broadband data transfer and low latency electrical communication between a high-capacity memory and a logic device interconnected by a feedthrough interposer (FTI) featuring a 10 µm scale fine-wiring pattern and ultra-fine-pitch through vias. This technology features co-existence of the wide-band memory accessibility of a system-on-chip (SoC) and the capability of memory capacity increasing of a system-in-package (SiP) that is made possible by the individual fabrication of memory and logic on independent chips. This technology can improve performance due to memory band widening and a reduction in the power consumed in inter-chip communications. This paper describes the concept, structure, process, and experimental results of prototypes of this package, called SMAFTI (SMAart chip connection with FeedThrough Interposer). This paper also reports the results of the fundamental reliability test of this novel inter-chip connection structure and board-level interconnectivity tests.

Spectrum sensing is a key technology within Cognitive Radio (CR) systems. Cooperative spectrum sensing using a distributed model provides improved detection for the primary user, which opens the CR system to a new security threat. This threat is the decrease of the cooperative sensing performance due to the spectrum sensing data falsification which is generated from malicious users. Our proposed scheme, based on robust statistics, utilizes only available past sensing nodes' received power data for estimating the distribution parameters of the primary signal presence and absence hypotheses. These estimated parameters are used to perform the Dempster-Shafer theory of evidence data fusion which causes the elimination of malicious users. Furthermore, in order to enhance performance, a node's reliability weight is supplemented along with the data fusion scheme. Simulation results indicate that our proposed scheme can provide a powerful capability in eliminating malicious users as well as a high gain of data fusion under various cases of channel condition.

This paper presents an efficient algorithm for incremental buffer insertion and module resizing for a full-placed floorplan. Our algorithm offers a method to use the white space in a given floorplan to resize modules and insert buffers, and at the same time keeps the resultant floorplan as close to the original one as possible. Both the buffer insertion and module resizing are modeled as geometric programming problems, and can be solved extremely efficiently using new developed solution methods. The experimental results suggest that the the wire length difference between the initial floorplan and result are quite small (less than 5%), and the global structure of the initial floorplan are preserved very well.

The performance of two-way amplify-and-forward (AF) relay networks is presented. In particular, we derive exact closed-form expressions for symbol error rate (SER), average sum-rate, and outage probability of two-way AF relay systems in independent but not identically distributed (i.n.i.d.) Rayleigh fading channels. Our analysis is validated by a comparison against the results of Monte-Carlo simulations.

At work, at home, and in some public places, a desktop PC is usually available nowadays. Therefore, it is important for users to be able to play various videos on different PCs smoothly, but the diversity of codec types complicates the situation. Although some mainstream media players can try to download the needed codec automatically, this may fail for average users because installing the codec usually requires administrator privileges to complete, while the user may not be the owner of the PC. We believe an ideal solution should work without users' intervention, and need no special privileges. This paper proposes such a user-friendly, program-transparent solution for Windows-based media players. It runs the media player in a user-mode virtualization environment, and then downloads the needed codec on-the-fly. Because of API (Application Programming Interface) interception, some resource-accessing API calls from the player will be redirected to the downloaded codec resources. Then from the viewpoint of the player, the necessary codec exists locally and it can handle the video smoothly, although neither system registry nor system folders was modified during this process. Besides convenience, the principle of least privilege is maintained and the host system is left clean. This paper completely analyzes the technical issues and presents such a prototype which can work with DirectShow-compatible players. Performance tests show that the overhead is negligible. Moreover, our solution conforms to the Software-As-A-Service (SaaS) mode, which is very promising in the Internet era.

A multiuser beamforming algorithm using codebook is proposed in this letter to reduce inter-user interference and improve the throughput of the downlink of multiuser MIMO systems. Basing on the minimal leakage criterion, we combine the codebook selection, limited feedforward and MMSE detection method in the new proposed algorithm. It not only improves the performance of systems, but also reduces the computational complexity at transmitter. Simulation results shows that the proposed algorithm has better performance than conventional beamforming methods.

By using multiple repeated signal replicas to formulate the accumulative observed noisy signal sequence (AONSS) or the differential observed noisy signal sequence (DONSS) in the hybrid ARQ system, a novel data-aided maximum likelihood (DA ML) SNR estimation and a blind ML SNR estimation technique are proposed for the AWGN channel. It is revealed that the conventional DA ML estimate is a special case of the novel DA ML estimate, and both the proposed DA ML and the proposed blind ML SNR estimation techniques can offer satisfactory SNR estimation without introducing significant additional complexity to the existing hybrid ARQ scheme. Based on the AONSS, both the generalized deterministic and the random Cramer-Rao lower bounds (GCRLBs), which include the traditional Cramer-Rao lower bounds (CRLBs) as special cases, are also derived. Finally, the applicability of the proposed SNR estimation techniques based on the AONSS and the DONSS are validated through numerical analysis and simulation results.

Secure operating systems (secure OSes) are widely used to limit the damage caused by unauthorized access to Internet servers. However, writing a security policy based on the principle of least privilege for a secure OS is a challenge for an administrator. Considering that remote attackers can never attack a server before they establish connections to it, we propose a novel scheme that exploits phases to simplify security policy descriptions for Internet servers. In our scheme, the entire system has two execution phases: an initialization phase and a protocol processing phase. The initialization phase is defined as the phase before the server establishes connections to its clients, and the protocol processing phase is defined as the phase after it establishes connections. The key observation is that access control should be enforced by the secure OS only in the protocol processing phase to defend against remote attacks. Since remote attacks cannot be launched in the initialization phase, a secure OS is not required to enforce access control in this phase. Thus, we can omit the access-control policy in the initialization phase, which effectively reduces the number of policy rules. To prove the effectiveness of our scheme, we wrote security policies for three kinds of Internet servers (HTTP, SMTP, and POP servers). Our experimental results demonstrate that our scheme effectively reduces the number of descriptions; it eliminates 47.2%, 27.5%, and 24.0% of policy rules for HTTP, SMTP, and POP servers, respectively, compared with an existing SELinux policy that includes the initialization of the server.

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.

High Altitude Platform Stations (HAPS) are recently considered as a green infrastructure to provide high speed multimedia services. The critical issue of HAPS is frequency sharing with satellite systems. Regulating antenna beam pattern using adaptive antenna schemes is one of means to facilitate the sharing with a space receiver for fixed satellite services on the uplink of a HAPS system operating in U bands. In this letter, we investigate antenna beam pattern characteristics of HAPS user terminals with various values of scan angles of main beam, null position angles, and null width.

Cognitive radio systems offer the opportunity to improve the spectrum utilization by detecting unused frequency bands while avoiding interference to primary users. This paper proposes a new algorithm for spectrum sensing, which is an energy detector using a hybrid (adaptive and fixed) threshold, in order to compensate the weak points of the existing energy detector in the distorted communication channel environment. Simulation results are presented which show that the performance of the new proposed scheme is better than the existing scheme using a fixed threshold or an adaptive threshold. Additionally, the performance is investigated in terms of several parameters such as the mobile speed and the probability of false alarms. The simulation results also show that the proposed algorithm makes the detector highly robust against fading, shadowing, and interference.

Content sharing mechanisms in current DRM systems are based on a domain where multiple devices have the same domain key. This can lead to a security weakness as failure of one device means revocation of a domain itself. Furthermore, if a device leaves the domain, all the other devices should update their domain key. This also leads to efficiency problem. This paper proposes the new content sharing scheme based on the user binding DRM without the use of domain key. The proposed scheme improves the previous domain technology in terms of security and efficiency as it removes the use of domain key and only allows content sharing for multiple devices owned by the same user.

Location Based Services (LBS) are expected to become one of the major drivers of ubiquitous services due to recent inception of GPS-enabled mobile devices, the development of Web2.0 paradigm, and emergence of 3G broadband networks. Having this vision in mind, Community Context-attribute-oriented Collaborative Information Environment (CCCIE) based Autonomous Decentralized Community System (ADCS) is proposed to enable provision of services to specific users in specific place at specific time considering various context-attributes. This paper presents autonomous community construction technology that share service discovered by one member among others in flexible way to improve timeliness and reduce network cost. In order to meet crucial goal of real-time and context-aware community construction (provision of service/ service information to users with common interests), and defining flexible service area in highly dynamic operating environment of ADCS, proposed progressive ripple based service discovery technique introduces novel idea of snail's pace and steady advancing search followed by swift boundary confining mechanism; while service area construction shares the discovered service among members in defined area to further improve timeliness and reduce network cost. Analysis and empirical results verify the effectiveness of the proposed technique.

We propose a novel adaptive segment repair mechanism to improve traditional MPLS (Multi-Protocol Label Switching) failure recovery. The proposed mechanism protects one or more contiguous high failure probability links by dynamic setup of segment protection. Simulations demonstrate that the proposed mechanism reduces failure recovery time while also increasing network resource utilization.

This paper describes the application techniques of the latency insertion method (LIM) to CMOS circuit simulations. Though the existing LIM algorithm to CMOS circuit performs fast transient analysis, CMOS circuits are not modeled accurately. As a result, they do not provide accurate simulations. We propose a more accurate LIM scheme for the CMOS inverter circuit by adopting a more accurate model of the CMOS inverter characteristics. Moreover, we present the way to expand the LIM algorithm to general CMOS circuit simulations. In order to apply LIM to the general CMOS circuits which consist of CMOS NAND and NOR, we derive the updating formulas of the explicit form of the LIM algorithm. By using the explicit form of the LIM scheme, it becomes easy to take in the characteristics of CMOS NAND and NOR into the LIM simulations. As a result, it is confirmed that our techniques are useful and efficient for the simulations of CMOS circuits.

We propose a complexity-reducing algorithm for serial scheduled min-sum decoding that reduces the number of check nodes to process during an iteration. The check nodes to skip are chosen based on the reliability, a syndrome and a log-likelihood-ratio (LLR) value, of the incoming messages. The proposed algorithm is evaluated by computer simulations and shown to reduce the decoding complexity about 20% compared with a conventional serial scheduled min-sum decoding with small fractional decibel degradation in error correction performance.

Networking technologies have recently been evolving and network applications are now expected to support flexible composition of upper-layer network services, such as security, QoS, or personal firewall. We propose a multi-platform framework called FreeNA* that extends existing applications by incorporating the services based on user definitions. This extension does not require users to modify their systems at all. Therefore, FreeNA is valuable for experimental system usage. We implemented FreeNA on both Linux and Microsoft Windows operating systems, and evaluated their functionality and performance. In this paper, we describe the design and implementation of FreeNA including details on how to insert network services into existing applications and how to create services in a multi-platform environment. We also give an example implementation of a service with SSL, a functionality comparison with relevant systems, and our performance evaluation results. The results show that FreeNA offers finer configurability, composability, and usability than other similar systems. We also show that the throughput degradation of transparent service insertion is 2% at most compared with a method of directly inserting such services into applications.