Device-parameter estimation sensors inside a chip are gaining its importance as the post-fabrication tuning is becoming of a practical use. In estimation of variational parameters using on-chip sensors, it is often assumed that the outputs of variation sensors are not affected by random variations. However, random variations can deteriorate the accuracy of the estimation result. In this paper, we propose a device-parameter estimation method with on-chip variation sensors explicitly considering random variability. The proposed method derives the global variation parameters and the standard deviation of the random variability using the maximum likelihood estimation. We experimentally verified that the proposed method improves the accuracy of device-parameter estimation by 11.1 to 73.4% compared to the conventional method that neglects random variations.

This paper presents a 65-nm CMOS 8-antenna array transmitter operating in 117–130-GHz range for short range and portable millimeter-wave (mm-wave) active imaging applications. Each antenna element is a new on-chip antenna located on the top metal. By using on-chip transformer, pulse output of each resistor-less mm-wave pulse generators (PG) are sent to each integrated antenna. To adjust pulse delays for the purpose of pulse beam-forming, a 7-bit digitally programmable delay circuit (DPDC) is added to each of PGs. Moreover, in order to dynamically adjust pulse delays among eight SW's outputs, we implemented on-chip jitter and relative skew measuring circuit with 20-bit digital output to achieve cumulative distribution (CDF) and probability density (PDF) functions from which DPDC's input codes are decided to align eight antenna's output pulses. Two measured radiation peaks after relative skew alignment are obtained at (θ; φ) angles of (-56; 0) and (+57; 0). Measurement results shows that beam-forming angles of the fully integrated antenna array can be adjusted by digital input codes and by the on-chip skew adjustment circuit for active imaging applications.

Thin film glucose biosensors were fabricated with organic/inorganic hybrid films based on glucose oxidase (GOx) and Prussian Blue nano-clusters. The biosensors composed of hybrid films were characterized by the low operating potential and the advantage to interference-free detection. In this research, we employed two kinds of thin films for GOx immobilization: Langmuir-Blodgett (LB) and self-assembled monolayer (SAM). The LB film immobilizes GOx in its inside through the electrostatic force, while the SAM immobilizes GOx with the covalent bond. The sensors with LB film produced a relatively high current signal, while the non-linear behavior and a low stability were recognized. On the other hand, the sensors with SAM presented a good linear relationship and a very stable performance.

Emerging video surveillance technologies are based on foreground detection to achieve event detection automatically. Integration foreground detection with a modern multi-camera surveillance system can significantly increase the surveillance efficiency. The foreground detection often leads to high computational load and increases the cost of surveillance system when a mass deployment of end cameras is needed. This paper proposes a DSP-based foreground detection algorithm. Our algorithm incorporates a temporal data correlation predictor (TDCP) which can exhibit the correlation of data and reduce computation based on this correlation. With the DSP-oriented foreground detection, an adaptive frame rate control is developed as a low cost solution for multi-camera surveillance system. The adaptive frame rate control automatically detects the computational load of foreground detection on multiple video sources and adaptively tunes the TDCP to meet the real-time specification. Therefore, no additional hardware cost is required when the number of deployed cameras is increased. Our method has been validated on a demonstration platform. Performance can achieve real-time CIF frame processing for a 16-camera surveillance system by single-DSP chip. Quantitative evaluation demonstrates that our solution provides satisfied detection rate, while significantly reducing the hardware cost.

The Workflow Management Coalition, WfMC for short, has given a protocol for interorganizational workflows, interworkflows for short. In the protocol, an interworkflow is constructed by connecting two or more existing workflows; and there are three models to connect those workflows: chained, nested, and parallelsynchronized. Business continuity requires the interworkflow to preserve the behavior of the existing workflows. This requirement is called behavioral inheritance, which has three variations: protocol inheritance, projection inheritance, and life-cycle inheritance. Van der Aalst et al. have proposed workflow nets, WF-nets for short, and have shown that the behavioral inheritance problem is decidable but intractable. In this paper, we first show that all WF-nets of the chained model satisfy life-cycle inheritance, and all WF-nets of the nested model satisfy projection inheritance. Next we show that soundness is a necessary condition of projection inheritance for an acyclic extended free choice WF-net of the parallelsynchronized model. Then we prove that the necessary condition can be verified in polynomial time. Finally we show that the necessary condition is a sufficient condition if the WF-net is obtained by connecting state machine WF-nets.

With advances in communication technologies, network services provided via the Internet have become widely diversified, and people can use these services not only via wired networks but also via wireless networks. There are several wireless systems in practical use such as cellular, WiMAX and WiFi. Although these wireless network systems have developed independently of each other, they should be integrated for seamless access by users. However, each system uses an individual spectrum prescribed by law to avoid radio interference. To overcome such a situation, dynamic spectrum access technology is receiving much attention. We propose a dynamic spectrum assignment method in which a WiFi system temporarily uses a spectrum band of the WiMAX system in WiFi/WiMAX integrated networks to reduce call blocking probability of multimedia communication services. We confirm the effectiveness of the proposed method by simulation experiments.

In heterogeneous cellular networks (HCN), which consists of macrocells and picocells, efficient interference management schemes between macrocells and picocells are crucial to the overall system performance. We propose a dynamic cooperative silencing (DCS) scheme for intercell interference control (ICIC). It is a low-complexity, low-feedback and distributed algorithm using only strongly interfered neighboring user information. A system simulation shows that the system performance and in particular the cell-edge throughput is significantly increased with the proposed silencing scheme.

Carrier aggregation (CA) is one of the most important techniques for LTE-Advanced because of its capability to support a wide transmission bandwidth of up to 100 MHz and heterogeneous networks effectively while achieving backward compatibility with the Release 8 LTE. In order to improve the performance of control information transmission in heterogeneous networks, cross-carrier scheduling is supported, i.e., control information on one component carrier (CC) can assign radio resources on another CC. To convey the control information efficiently, a search space is defined and used in Release 8 LTE. In cross-carrier scheduling, the optimum design for the search space for different CCs is a paramount issue. This paper presents two novel methods for search space design. In the first method using one hash function, a user equipment (UE)-specific offset is introduced among search spaces associated with different CCs. Due to the UE-specific offsets, search spaces of different UEs are staggered and the probability that the search space of one UE is totally overlapped by that of another UE can be greatly reduced. In the second method using multiple hash functions, a novel randomization scheme is proposed to generate independent hash functions for search spaces of different CCs. Because of the perfect randomization effect of the proposed method, search space overlapping of different UEs is reduced. Simulation results show that both the proposed methods effectively reduce the blocking probability of the control information compared to existing methods.

In this letter, we show that the code-trellis and the error-trellis for a convolutional code can be reduced simultaneously, if reduction is possible. Assume that the error-trellis can be reduced by shifting particular error-subsequences. In this case, if the identical shifts occur in the corresponding subsequences of each code-path, then the code-trellis can also be reduced. First, we obtain pairs of transformations which generate the identical shifts both in the subsequences of the code-path and in those of the error-path. Next, by applying these transformations to the generator matrix and the parity-check matrix, we show that reduction of these matrices is accomplished simultaneously, if it is possible. Moreover, it is shown that the two associated trellises are also reduced simultaneously.

This letter proposes a spread spectrum audio watermarking robust against playback speed modification (PSM) attack which introduces both time-scale modification and pitch shifting. Two important improvements are exploited to achieve this robustness. The first one is selecting an embedding region according to the stable characteristic of the audio energy. The second one is stretching the pseudo-random noise sequence to match the length of the embedding region before embedding and detection. Experimental results show that our method is highly robust to common audio signal processing attacks and synchronization attacks including PSM, cropping, trimming and jittering.

In this paper, we propose new constructions of binary sequences based on an interleaving technique. In our constructions, we make use of any binary sequences with ideal 2-level autocorrelation, a special shift sequence as well as the perfect binary sequence or sequence (0,1,1) in the interleaved structure to get the new sequences. Except for the most autocorrelation values of our new sequences, we find that the unexpected autocorrelation values only occur four or two times in each period no matter how long the period is. We state that the sequences have a good autocorrelation in this case. In particular, the autocorrelation distribution of our sequences is determined.

In this paper, we propose an adaptive Go-Back-N (GBN) ARQ protocol over two parallel channels with slow state transition. This proposed protocol sophisticatedly determines the order of priority of the channel usage for sending packets, by using the channel-state feedback information. We exactly analyze the throughput efficiency of the protocol and obtain its closed-form expression under the assumption that the time-varying channel is modeled by a two-state Markov chain, which is characterized by packet error rate and the decay factor. The analytical results and numerical examples show that, for a given round-trip time, the throughput efficiency depends on both the average packet-error rate and the decay factor. Furthermore, it is shown that the throughput efficiency of the proposed protocol is superior to that of the non-adaptive Go-Back-N protocol using the two channels in a fixed order in the case of slow state transition (i.e. the decay factor is positively large).

A readout circuit incorporating a pixel-level analog-to-digital converter (ADC) is studied for 2-dimensional microbolometer infrared focal plane arrays (IRFPAs). The integration time and signal-to-noise ratio (SNR) is improved using the current-mode bias and MSB skimming. The proposed pixel-level ADC is a two-step configuration, so its power consumption is very low. The readout circuit was designed using a 0.35 µm 2-poly 4-metal CMOS process for a 320240 microbolometer array with a pixel size of 35µm35µm. The noise equivalent temperature difference (NETD) was estimated to be 47 mK, with a power consumption of 390 nW for a pixel-level ADC.

We fabricated solution-processed organic complementary inverters based on α,ω-bis(2-hexyldecyl)sexithiophene (BHD6T) for p-channel and C60-fused N-methylpyrrolidine-meta-dodecyl phenyl (C60MC12) for n-channel. The BHD6T and C60MC12 thin-film transistors showed high field-effect mobilities of 0.035 and 0.057 cm2/Vs, respectively. The complementary inverter with a supply voltage of 50 V exhibited inverting voltages of 26.8 V for forward and 27.0 V for backward sweeps and a high gain of 76.

The specific absorption rate (SAR) measurement procedure for wireless communication devices used in close proximity to the human body other than the ear was standardized by the International Electrotechnical Commission (IEC). This procedure is applicable to SAR measurement of data communication terminals that are used with host devices. Laptop PCs are assumed as host devices in this study. First, numerical modeling of laptop PCs and the validity of computations are verified with corresponding measurements. Next, mass averaged SARs are calculated dependent on the dimensions of the laptop PCs and the position of the terminals. The results show that the ratio of the maximum to minimum SARs is at most 2.0 for USB dongle and card-type terminals at 1950 MHz and 835 MHz.

For measuring the similarity of biological sequences and structures such as DNA sequences, protein sequences, and tertiary structures, several compression-based methods have been developed. However, they are based on compression algorithms only for sequential data. For instance, protein structures can be represented by two-dimensional distance matrices. Therefore, it is expected that image compression is useful for measuring the similarity of protein structures because image compression algorithms compress data horizontally and vertically. This paper proposes series of methods for measuring the similarity of protein structures. In the methods, an original protein structure is transformed into a distance matrix, which is regarded as a two-dimensional image. Then, the similarity of two protein structures is measured by a kind of compression ratio of the concatenated image. We employed several image compression algorithms, JPEG, GIF, PNG, IFS, and SPC. Since SPC often gave better results among the other image compression methods, and it is simple and easy to be modified, we modified SPC and obtained MSPC. We applied the proposed methods to clustering of protein structures, and performed Receiver Operating Characteristic (ROC) analysis. The results of computational experiments suggest that MSPC has the best performance among existing compression-based methods. We also present some theoretical results on the time complexity and Kolmogorov complexity of image compression-based protein structure comparison.

In wireless sensor networks constructed from battery driven nodes, it is difficult to supply electric power to the nodes. Because of this, the power consumption must be reduced. To cope with this problem, clustering techniques have been proposed. EACLE is a method that uses a clustering technique. In EACLE, route selection is executed independently after the CH (Cluster Head) selection. This two-phase control approach increases overheads and reduces the battery power, which shortens the lifetime of wireless sensor networks. To cope with this problem, we have proposed a novel routing and clustering method called PARC for wireless sensor networks that reduces these overheads by integrating the cluster selection phase and the route construction phase into a single phase. However, PARC has a weak point in that the batteries of CHs around the sink node are depleted earlier than the other nodes and the sink node cannot collect sensing data. This phenomenon is called the hot spot problem. In order to cope with this problem of PARC, we propose PARC+, which extends the CH selection method of PARC such as more nodes around the sink can be selected as a CH node. We evaluate our proposed methods by simulation experiments and show its effectiveness.

In multi-cell wireless systems with insufficient frequency reuse, the downlink transmission suffers from other cell interference (OCI). The cooperative transmission among multiple base stations is an effective way to mitigate OCI and increase the system sum rate. An adaptive scheme for serving one user in each cell was proposed in [1]. In this paper, we generalize the scheme in [1] by serving more than one user in each cell with adaptive OCI cancelation. Based on our derived statistics of a user for different transmission strategies, we propose a low complexity transmission scheme that achieves near-maximal ergodic sum rate. Through numerical examples, we show that the system sum rate can be improved by selecting the appropriate transmission strategy combination adaptively. As a result, our proposed system can explore spatial multiplexing gain without additional power and thus improves the system sum rate significantly.

Coscheduling has been gained a resurgence of interest as an effective technique to enhance the performance of parallel applications in multi-programmed clusters. However, existing coscheduling schemes do not adequately handle priority boost conflicts, leading to significantly degraded performance. To address this problem, in our previous study, we devised a novel algorithm that reorders the scheduling sequence of conflicting processes based on the rescheduling latency of their correspondents in remote nodes. In this paper, we exhaustively explore the design issues and implementation details of our contention-aware coscheduling scheme over Myrinet-based cluster system. We also practically analyze the impact of various system parameters and job characteristics on the performance of all considered schemes on a heterogeneous Linux cluster using a generic coscheduling framework. The results show that our approach outperforms existing schemes (by up to 36.6% in avg. job response time), reducing both boost conflict ratio and overall message delay.

In this paper, a distributed cooperative multicell beamforming algorithm is proposed, and a detail analysis and solving method for instantaneous and statistical channel state information (CSI) are presented. Firstly, an improved distributed iterative beamforming algorithm is proposed for the multiple-input single-output interference channel (MISO IC) scenario which chooses virtual signal-to-interference-and-noise (SINR) as decision criterion to initialize and then iteratively solves the constrained optimization problem of maximizing the virtual SINR for a given level of generated interference to other users. Then, the algorithm is generalized to the multicell date sharing scenario with a heuristics power allocation scheme based on a viewpoint of the layered channel. Finally, the performance is illustrated through numerical simulations.