The proliferation of many-core architectures has led to the explosive development of parallel applications using programming models, such as OpenMP, TBB, and Cilk/Cilk++. With increasing number of cores, however, it becomes even harder to efficiently schedule parallel applications on these resources since current many-core runtime systems still lack effective mechanisms to support collaborative scheduling of these applications. In this paper, we study feedback-driven adaptive scheduling based on work stealing, which provides an efficient solution for concurrently executing a set of applications on many-core systems. To dynamically estimate the number of cores desired by each application, a stable feedback-driven adaptive algorithm, called SAWS, is proposed using active workers and the length of active deques, which well captures the runtime characteristics of the applications. Furthermore, a prototype system is built by extending the Cilk runtime system, and the experimental results, which are obtained on a Sun Fire server, show that SAWS has more advantages for scheduling concurrent parallel applications. Specifically, compared with existing algorithms A-Steal and WS-EQUI, SAWS improves the performances by up to 12.43% and 21.32% with respect to mean response time respectively, and 25.78% and 46.98% with respect to processor utilization, respectively.

This letter considers a dual-hop multiuser MIMO amplify-and-forward relay broadcast system with multi-antenna nodes. A unified scheme is addressed to jointly optimize the linear transceiver based on the sum mean-square error (MSE) and the sum rate criterion. The solutions are iteratively obtained by deriving the gradients of the objective functions for a gradient descent algorithm. Simulation results demonstrate the performance improvements in terms of the BER and the sum rate.

A method of generating scenarios using differential scenaro information is presented. Behaviors of normal scenarios of similar purpose are quite similar each other, while actors and data in scenarios are different among these scenarios. We derive the differential information between them and apply the differential information to generate new alternative/exceptional scenarios. Our method will be illustrated with examples. This paper describes (1) a language for describing scenarios based on a simple case grammar of actions, (2) introduction of the differential scenario, and (3) method and examples of scenario generation using the differential scenario.

In a large queuing system, the effect of the ratio of the filled data on the queue and waiting time from the head of a queue to the service gate are important factors for process efficiency because they are too large to ignore. However, many research works assumed that the factors can be considered to be negligible according to the queuing theory. Thus, the existing queuing models are not applicable to the design of large-scale systems. Such a system could be used as a product classification center for a home delivery service. In this paper, we propose a tree-queue model for large-scale systems that is more adaptive to efficient processes compared to existing models. We analyze and design a mean waiting time equation related to the ratio of the filled data in the queue. Based on simulations, the proposed model demonstrated improvement in process-efficiency, and it is more suitable to realistic system modeling than other compared models for large-scale systems.

We propose a network coordinated opportunistic beamforming (NC-OBF) protocol for downlink K-cell networks with M-antenna base stations (BSs). In the NC-OBF scheme, based on pseudo-randomly generated BF vectors, a user scheduling strategy is introduced, where each BS opportunistically selects a set of mobile stations (MSs) whose desired signals generate the minimum interference to the other MSs. Its performance is then analyzed in terms of degrees-of-freedom (DoFs). As our achievability result, it is shown that KM DoFs are achievable if the number N of MSs in a cell scales at least as SNRKM-1, where SNR denotes the received signal-to-noise ratio. Furthermore, by deriving the corresponding upper bound on the DoFs, it is shown that the NC-OBF scheme is DoF-optimal. Note that the proposed scheme does not require the global channel state information and dimension expansion, thereby resulting in easier implementation.

Many studies and systems that incorporate elements such as “pleasure” and “fun” in the game to improve a learner's motivation have been developed in the field of learning environments. However, few are the studies of situations where many learners gather at a single computer and participate in a game-based learning environment (GBLE), and where the GBLE designs the learning process by controlling the interactions between learners such as competition, collaboration, and learning by teaching. Therefore, the purpose of this study is to propose a framework of educational control that induces and activates interaction between learners intentionally to create a learning opportunity that is based on the knowledge understanding model of each learner. In this paper, we explain the design philosophy and the framework of our GBLE called “Who becomes the king in the country of mathematics?” from a game viewpoint and describe the method of learning support control in the learning environment. In addition, we report the results of the learning experiment with our GBLE, which we carried out in a junior high school, and include some comments by a principal and a teacher. From the results of the experiment and some comments, we noticed that a game may play a significant role in weakening the learning relationship among students and creating new relationships in the world of the game. Furthermore, we discovered that learning support control of the GBLE has led to activation of the interaction between learners to some extent.

Silicon Physical Unclonable Functions (PUFs) have been proposed to exploit inherent characteristics caused by process variations, such as transistor size, threshold voltage and so on, and to produce an inexpensive and tamper-resistant device such as IC identification, authentication and key generation. We have focused on the arbiter-PUF utilizing the relative delay-time difference between the equivalent paths. The conventional arbiter-PUF has a technical issue, which is low uniqueness caused by the ununiformity on response-generation. To enhance the uniqueness, a novel arbiter-based PUF utilizing the Response Generation according to the Delay Time Measurement (RG-DTM) scheme, has been proposed. In the conventional arbiter-PUF, the response 0 or 1 is assigned according to the single threshold of relative delay-time difference. On the contrary, the response 0 or 1 is assigned according to the multiple threshold of relative delay-time difference in the RG-DTM PUF. The conventional and RG-DTM PUF were designed and fabricated with 0.18 µm CMOS technology. The Hamming distances (HDs) between different chips, which indicate the uniqueness, were calculated by 256-bit responses from the identical challenges on each chip. The ideal distribution of HDs, which indicates high uniqueness, is achieved in the RG-DTM PUF using 16 thresholds of relative delay-time differences. The generative stability, which is the fluctuation of responses in the same environment, and the environmental stability, which is the changes of responses in the different environment were also evaluated. There is a trade-off between high uniqueness and high stability, however, the experimental data shows that the RG-DTM PUF has extremely smaller false matching probability in the identification compared to the conventional PUF.

We propose a distributed node selection (DNS) scheme that guarantees quality of service (QoS) of the scalable video broadcasting system over wireless channels. The proposed DNS scheme chooses the destination node based on the SVC layer information, and it selects the best relay from a set of competing candidate nodes by considering two factors: 1) wireless channel conditions between destination and relay candidates and 2) scalable video's layer information. In simulations, the performance of the proposed scheme in terms of quality gains, complexity (overhead) and applicability was examined.

We estimated the transit time of GaInAs/AlAs double-barrier resonant tunneling diodes (RTDs) oscillating at 0.6–1 THz. The RTDs have graded emitter structures and thin barriers, and are integrated with planar slot antennas for the oscillation. The transit time across the collector depletion region was estimated from measured results of the dependence of oscillation frequency on RTD mesa area. The estimated transit time was slightly reduced with the introduction of the graded emitter, probably due to reduction of the electron transition between Γ and L bands resulted from the low electric field in the collector depletion region.

In this letter, we investigate the performance impact of disjoint multiple paths on SCTP in the connected MANET under emergency situations. Disjoint multiple paths allow multi-homing of SCTP to be fully utilized in MANETs, but it may cause inappropriate SACK handling. Through simulations, we evaluate the impact in terms of throughput and energy efficiency.

In this paper, we investigate two improved turbo receivers for the Long Term Evolution (LTE) uplink in the presence of transmitter (Tx) in-phase and quadrature-phase imbalance (IQI) with parameters known at eNodeB. For multiuser multiple-input multiple-output (MU-MIMO) single-carrier frequency division multiple access (SC-FDMA) systems, we derive a optimal joint linear minimum mean square error (MMSE) turbo multiuser detector (MUD) based on the mirror symmetry clusters. For the single use SC-FDMA system with Tx IQI, we derive an optimal widely linear MMSE (WLMMSE) turbo equalizer. Both receivers are implemented in the discrete frequency domain and only slightly increase the computational complexity compared to the conventional turbo receivers. Monte Carlo simulations show that the proposed receivers significantly outperform the conventional turbo receivers. The simulation results are then confirmed by the extrinsic information transfer (EXIT) chart analysis.

In the present paper, we address the problem of extrapolating group proximities from member relations, which we refer to as the group proximity problem. We assume that a relational dataset consists of several groups and that pairwise relations of all members can be measured. Under these assumptions, the goal is to estimate group proximities from pairwise relations. In order to solve the group proximity problem, we present a method based on embedding and distribution mapping, in which all relational data, which consist of pairwise dissimilarities or dissimilarities between members, are transformed into vectorial data by embedding methods. After this process, the distributions of the groups are obtained. Group proximities are estimated as distances between distributions by distribution mapping methods, which generate a map of distributions. As an example, we apply the proposed method to document and bacterial flora datasets. Finally, we confirm the feasibility of using the proposed method to solve the group proximity problem.

With the development of COMPASS system, finding suitable and efficient multiplexing solutions have become important for the system signal design. In this paper, based on the alternative BOC (AltBOC) modulation technique, the multiplexing scheme for COMPASS Phase II B1 signals is proposed. Then, to combine all COMPASS Phase III (CP III) B1 components into a composite signal with constant envelope, the generalized majority voting (GMV) technique is employed based on the characteristics of CP III B1 signals. The proposed multiplexing schemes also provide potential opportunities for GNSS modernization and construction, such as GPS, Galileo, etc.

We give characterizations of stable scaling functions with compact band regions, which have the oversampling property.

This letter proposes an algorithm of determining the BER-minimized block delay for detection and the associated precoder design once the channel state information and limited transmission power are given. Simulation cases demonstrate the adjusting capability of the proposed algorithm for achieving best BER performance of the joint linear transceiver design.

We have developed a portable NIRS-based optical BCI system that features a non-invasive, facile probe attachment and does not require muscle movement to control the target devices. The system consists of a 2-channel probe, a signal-processing unit, and an infrared-emission device, which measures the blood volume change in the participant's prefrontal cortex in a real time. We use the threshold logic as a switching technology, which transmits a control signal to a target device when the electrical waveforms exceed the pre-defined threshold. Eight healthy volunteers participated in the experiments and they could change the television channel or control the movement of a toy robot with average switching times of 11.5 ± 5.3 s and the hit rate was 83.3%. These trials suggest that this system provides a novel communication aid for people with motor disabilities.

Joint transmission (JT) in time-division-duplex code-division multiple-access (TDD-CDMA) systems can provide a low peak-to-average power ratio (PAPR) for single paths, but causing a high PAPR in multipath environments. To avoid the high PAPR, we propose a new approach to JT technique by selecting certain paths instead of all paths used in JT processing so that PAPR becomes lower. The path selection proposal involves two methods; path selection by taking certain paths from all paths and by taking paths having path gains above a certain threshold value. To enhance the effectiveness of the proposed techniques, we evaluate a combination of the proposed technique with the clipping technique. We evaluate both PAPR and bit error rate (BER) performance for the proposed techniques and its combination with the clipping technique. We compare the results of the proposed techniques with conventional JT technique and the combination techniques with clipping technique. From the results of computer simulation, we show that the proposed path selection techniques perform low PAPR and good BER performance compared to the conventional JT processing. We also show that the combination of proposed path selection technique and clipping performs low PAPR performance without severe BER degradation compared to the conventional clipping technique.

In deep-submicron era, wire delay is becoming a bottleneck while pursuing higher system clock speed. Several distributed register (DR) architectures are proposed to cope with this problem by keeping most wires local. In this article, we propose the distributed register-file microarchitecture with inter-island delay (DRFM-IID). Though DRFM-IID is also one of the DR-based architectures, it is considered more practical than the previously proposed DRFM, in terms of delay model. With such delay consideration, the synthesis task is inherently more complicated than the one without inter-island delay concern since uncertain interconnect latency is very likely to seriously impact on the whole system performance. Therefore we also develop a performance-driven architectural synthesis framework targeting DRFM-IID. Several factors for evaluating the quality of results, such as number of inter-island transfers, timing-criticality of transfer, and resource utilization balancing, are adopted as the guidance while performing architectural synthesis for better optimization outcomes. The experimental results show that the latency and the number of inter-cluster transfers can be reduced by 26.9% and 37.5% on average; and the latter is commonly regarded as an indicator for power consumption of on-chip communication.

This paper proposes a utility function-based scheduling algorithm for integrated real-time and non-real-time services in long-term evolution systems. The proposed utility function satisfies the target dropping ratio of real-time users; it uses the delay constraint and increases the throughput of non-real-time users by scheduling real-time users together with non-real-time users. Simulation results show that the proposed scheduling algorithm significantly improves the throughput of non-real-time users without sacrificing the quality of service of real-time users.

This letter proposes a practical algorithm for video transmission of the scalable extension of H.264/AVC (SVC) over limited bit-rate and varying channel signal-to-noise ratio (SNR). The proposal consists of SVC source-layer dropping and layered FEC using LDPC codes to maximize the video quality. The experimental results show that the proposed method realizes better video quality than the compared unequal error protection (UEP) without source-layer dropping. This implies that the dropping of a certain number of source-layers and using the resultant bit-budget for channel coding is more effective than the other UEP case which uses all possible source-layers.