A portable biofuel cell with an anode modified with glucose oxidase/ferrocene and a cathode modified with bilirubin oxidase was fabricated on a flexible polyimide substrate. The anode and the cathode with an area of 3$ imes$10,mm$^2$ were separated with a gap of 1,mm. Solidified glucose biofuel units were prepared by solidifying 50--200,mM glucose aqueous solution containing 0.5--2.5% agarose. The influences of the biofuel volume and glucose concentrations on power generation were investigated. The maximum power density was almost independent on the agarose concentration, and it continuously decreased as time clasped possibly due to the consumption of glucose and/or release of the enzymes from the electrodes. The maximum power and power density were 0.32 $mu $W and 1.08,$mu $W/cm$^2$ at 0.17,V, respectively when the solidified hydrogel biofuel unit with a dimension of 13$ imes$24$ imes$4 mm$^3$ containing the 100,mM glucose aqueous solution and 2.5, wt% agarose was used. The biofuel cell continued to deliver the power density over 0.5,$mu $W/cm$^2$ for more than 1,h.

We deposited thin films of thiophene/phenylene co-oligomers (TPCOs) onto poly(tetrafluoroethylene) (PTFE) layers that were friction-transferred on substrates. These films were composed of aligned molecules in such a way that their polarizations of emissions and absorbances were larger along the drawing direction than those perpendicular to that direction. Organic field-effect transistors (OFETs) fabricated with these films indicated large mobilities, when the drawing direction of PTFE was parallel to the channel length direction. The friction-transfer technique forms the TPCO films that indicate the anisotropic optical and electronic properties.

We have investigated both the film thickness and surface potential of organic semiconductors deposited on two kinds of electrodes by the simultaneous observation with the dynamic force microscopy (DFM)/Kelvin-probe force microscope (KFM). To clarify the interfacial properties of organic semiconductor, we fabricated samples that imitated the organic light emitting diode (OLED) structure by depositing bis [$N,N '$-(1-naphthyl)-$N,N '$-phenyl] benzidine ($alpha$-NPD) and tris (8-hydroxyquinolinato) aluminum (Alq$_{3}$), respectively, on indium-tin-oxide (ITO) as anode and aluminum (Al) as cathode by the vacuum evaporation deposition using intersecting metal shadow masks. This deposition technique enables us to fabricate four different areas in the same substrate. The crossover area of the deposited thin films were measured by the DFM/KFM, the energy band diagrams were depicted and we considered that the charge behavior of the organic semiconductor depended on the material and the structure.

We fabricated organic field-effect transistors (OFETs) having a thin layer of molybdenum trioxide (MoO$_3$), a Lewis acid, and evaluated their electrical characteristics. The insertion of a thin MoO$_3$ layer reduces the on/off ratio but improves the apparent mobility of the charge carriers. To identify the dominant mechanism responsible for this effect, we characterized devices having a 69-nm-thick pentacene layer with a 1-nm-thick MoO$_3$ layer either between the gold source and the drain electrodes or only directly under these electrodes. The former device exhibited a low on/off ratio, whereas the latter device exhibited an on/off ratio comparable to those of conventional pentacene OFETs without a thin MoO$_3$ layer, suggesting that the formation of charge-transfer (CT) complexes immediately above the conduction channel is the critical mechanism. CT complexes at the pentacene/MoO$_3$ interface immediately above the conduction channel contribute to the formation of an effective channel for off-currents as well as drain currents. Moreover, we also attempted to improve the on/off ratio by using a cloth to rub the surface of a thin MoO$_3$ layer immediately above the conduction channel to create what we believe to be a profile with abrupt changes in height in the direction of the drain current conduction in OFETs. Consequently, it was found that such a rubbed MoO$_3$ layer had a surface with a scratched pattern, and the on/off ratio of the OFET was improved, indicating that controlling the CT complex formation by patterning a MoO$_3$ layer can reduce the off-current in OFETs having a pentacene/MoO$_3$ active layer.

The novel ladder-shaped polydiacetylene with a terephthalamide linker in the molecular center, namely poly(TPh-bisDA) was synthesized by photo-polymerization. The characteristics of thin films of polymer were dependent upon a casting solvent, but no significant change of backbone conformation of the PDA was observed. Obtained film is expected to be applied to the semi-conducting materials for organic field effect transistors (OFET).

We report a real time method to monitor the chemical reaction in microdroplets, which contain an organic dye, 5(6)-carboxynaphthofluorescein and a CdSe/ZnS quantum dot using fluorescence spectra. Especially, the relationship between the droplet size and the reaction rate of the two reagents was investigated by changing an injection speed.

Polyimide thin films were prepared by vapor-deposition polymerization. Naphthalene carboxylic dianhydride (NTCDA) was coevaporated with either diamino naphthalene (DAN) or diamino benzophenone (DAB). Coevaporation of dianhydride and diamines yielded thin films of polyamic acids. A polyimide thin film was obtained by annealing the codeposited film of NTCDA-DAB. On the other hand, the codeposited film of NTCDA-DAN was not imidized by annealing. In both cases, chemical structures of the products were not largely influenced by the molar ratio of depositing monomers if sufficient amount of diamine molecules are supplied in the coevaporation process.

In this study, flexible organic solar cells (OSCs) employing a solution-processed hole-transporting layer (HTL) and low temperature annealing active layer have been fabricated. Vanadium oxide (V$_{2}$O$_{5})$, poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), V$_{2}$O$_{5}$/PEDOT:PSS or PEDOT:PSS/V$_{2}$O$_{5}$ is used as the HTL. Poly(3-hexythiophene) (P3HT):[6,6]-phenyl C61-butyric acid methyl ester (PCBM) is used as the active layer. HTL and active layer are all formed by a spin coating method on polyethylene terephthalate (PET) substrates. The OSC configuration has been optimized in the study to be PET/ITO/V$_{2}$O$_{5}$/PEDOT:PSS/P3HT:PCBM/LiF/Al. Based on a low annealing temperature of 90$^{circ}$C for P3HT:PCBM and parameters optimization of solution-processed V$_{2}$O$_{5}$/PEDOT:PSS, the OSC demonstrates a current density (JSC) and power conversion efficiency (PCE) of 6.08, mA/cm$^{2}$ and 1.57%, while an OSC without the HTL has PCE around 0.06%. The V$_{2}$O$_{5}$/PEDOT:PSS stacked HTL provides not only a stepwise hole-transporting energy diagram configuration but a smooth film surface for coating P3HT:PCBM active layer, which subsequently increases charge carrier transporting capability and extracts holes from the active layer to the anode.

In this paper, we propose a secondary user (SU) resource assignment algorithm for a multi-hop (MH) cognitive radio network to improve the end-to-end throughput. In the MH networks used for spectrum sharing, each SU needs to improve the throughput by taking the primary user (PU) protection into account. For overcoming this problem, we estimate the PU acceptable received power, which is determined by the acknowledgment packet (ACK) power from the PU receiver at each SU. With this estimation, we propose an SU optimal transmit power control algorithm to not only maximize the end-to-end throughput of the SU MH flow but also maintain the considered PU acceptable interference power. In this study, a distributed joint allocation algorithm has been used to solve the optimization problem and to effectively allocate the power of each SU.

The dynamic routing and wavelength assignment (RWA) problem in wavelength division multiplexing (WDM) optical networks with sparse wavelength conversion has been a hot research topic in recent years. An optimized algorithm based on a multiple-layered interconnected graphic model (MIG) for the dynamic RWA is presented in this paper. The MIG is constructed to reflect the actual WDM network topology. Based on the MIG, the link cost is given by the conditions of available lightpath to calculate an initial solution set of optimal paths, and by combination with path length, the optimized solution using objective function is determined. This approach simultaneously solves the route selection and wavelength assignment problem. Simulation results demonstrate the proposed MIG-based algorithm is effective in reducing blocking probability and boosting wavelength resource utilization compared with other RWA methods.

In recent years, wireless power transfer has been attracting a great deal of attention. In order to realize efficient power transfer, it is necessary to communicate data such as a frequency, required power, or error tolerance. In the proposed system, because of the use of the same antennas for power transmission and data transmission, the frequency response of a channel for the data transmission changes owing to load fluctuation and the distance between antennas. This paper investigates data transmission performance in the wireless power transfer system with frequency response estimation at the transmitter side. The numerical results obtained through computer simulation show that the proposed scheme can estimate the frequency response of the channel and the difference between the expected bit error rate (BER) and the BER with the estimation error is less than 0.5dB at the BER of 10-3.

We show that, in practice, a network adversary can achieve decidedly non-negligible advantage in attacking provable key-protection properties; e.g., the “existential key recovery” security and “multi-key hiding” property of typical nonce-based symmetric encryption schemes whenever these schemes are implemented with standard block ciphers. We also show that if a probabilistic encryption scheme uses certain standard block ciphers (e.g., two-key 3DES), then enforcing the security bounds necessary to protect against network adversary attacks will render the scheme impractical for network applications that share group keys amongst many peers. The attacks presented here have three noteworthy implications. First, they help identify key-protection properties that separate the notion of indistinguishability from random bits (IND$) from the strictly weaker notion of indistinguishability of ciphertexts (IND); also, they help establish new relationships among these properties. Second, they show that nonce-based symmetric encryption schemes are typically weaker than probabilistic ones. Third, they illustrate the need to account for the Internet-level growth of adversary capabilities when establishing the useful lifetime of standard block-cipher parameters.

A secret sharing scheme is said to be d-multiplicative if the scheme allows the players to multiply shared d secrets by locally converting their shares into an additive sharing of the product. In the previous work, the following negative result for perfect secret sharing has been shown: The d-multiplicative secret sharing for d players is impossible. This paper extends the impossibility result to non-perfect secret sharing. Our main result is a proof that d-multiplicative secret sharing for d players is impossible even if every player has partial information on the secret (e.g., all but one bit). This result means that there is no need to relax the privacy requirement with leakage of partial information only for the purpose of d-multiplication.

In this letter, we propose a new intra-field deinterlacing algorithm based on an edge dependent weighted filter (EDWF). The proposed algorithm consists of three steps: 1) calculating the gradients of three directions (45°, 90°, and 135°) in the local working window; 2) achieving the weights of the neighboring pixels by exploiting the edge information in the pixel gradients; 3) interpolating the missing pixel using the proposed EDWF interpolator. Compared with existing deinterlacing methods on different images and video sequences, the proposed algorithm improves the peak signal-to-noise-ratio (PSNR) while achieving better subjective quality.

Electrostatic discharge (ESD) generators cause electromagnetic (EM) noises not only at ESD tests but also even before and after the tests. This may provide inconsistent test results, but the mechanism has not been well examined. To explain the mechanism qualitatively, we investigated a generation source model of EM noises from an ESD generator in conjunction with the functional control sequences of built-in relay switches and the DC high voltage power supply. To validate this model, we used a magnetic field probe to measure the induced EM noises before, during, and after contact and air discharges in accordance with the corresponding timing of the functional control sequences. As a result, we confirmed that the EM noises are induced when the relay switches operate before and at ESD testing and after ESD tests for both contact and air discharges. In addition, we found that the noise peaks due to contact discharges increase with charge voltages, and the peaks just before and at the testing are relatively larger than the ones after the tests, while the peaks of the induced noises at the air discharge testing do not always increase with charge voltages, but reach a maximum at 3kV. In addition, the peaks of the induced noises at the air discharge testing become smaller than either the peaks just before the testing and those after the tests at charge voltages above 6kV. This suggests that the EM noises just before ESD testing and after the test may cause the EUT to malfunction when air discharge tests with charge voltages over 6kV are conducted. A new control sequence of the built-in relay switch was also proposed for reducing the EM noises after ESD tests, which was validated through noise measurements.

We present a new method for generating thumbnail images from H.264/AVC coded bit streams. What distinguishes our approach from previous works is that it determines the thumbnail image pixels by summing the residual and estimate block averages. The residual block averages are directly acquired in the transform domain and the estimated block averages are calculated in the spatial domain. Due to the construction of the reference pixels in the spatial domain, the proposed method eliminates the source of mismatch error, thus the result does not suffer any degradation. The thumbnail images produced by the proposed method are indistinguishable to the ones by the method that decodes the H.264/AVC intra coded bit streams and then scales them down. For most images, the proposed method also executes almost 3 times faster than the down-scaling method at frequently used bandwidths.

In recent years, there has been a significant growth in the importance of data mining of graph-structured data due to this technology's rapid increase in both scale and application areas. Many previous studies have investigated decision tree learning on Semantic Web-based linked data to uncover implicit knowledge. In the present paper, we suggest a new random forest algorithm for linked data to overcome the underlying limitations of the decision tree algorithm, such as local optimal decisions and generalization error. Moreover, we designed a parallel processing environment for random forest learning to manage large-size linked data and increase the efficiency of multiple tree generation. For this purpose, we modified the previous candidate feature searching method of the decision tree algorithm for linked data to reduce the feature searching space of random forest learning and developed feature selection methods that are adjusted to linked data. Using a distributed index-based search engine, we designed a parallel random forest learning system for linked data to generate random forests in parallel. Our proposed system enables users to simultaneously generate multiple decision trees from distributed stored linked data. To evaluate the performance of the proposed algorithm, we performed experiments to compare the classification accuracy when using the single decision tree algorithm. The experimental results revealed that our random forest algorithm is more accurate than the single decision tree algorithm.

To determine the thickness from MR images, segmentation, that is, boundary detection, of the two adjacent thin structures (e.g., femoral cartilage and acetabular cartilage in the hip joint) is needed before thickness determination. Traditional techniques such as zero-crossings of the second derivatives are not suitable for the detection of these boundaries. A theoretical simulation analysis reveals that the zero-crossing method yields considerable biases in boundary detection and thickness measurement of the two adjacent thin structures from MR images. This paper studies the accurate detection of hip cartilage boundaries in the image plane, and a new method based on a model of the MR imaging process is proposed for this application. Based on the newly developed model, a hip cartilage boundary detection algorithm is developed. The in-plane thickness is computed based on the boundaries detected using the proposed algorithm. In order to correct the image plane thickness for overestimation due to oblique slicing, a three-dimensional (3-D) thickness computation approach is introduced. Experimental results show that the thickness measurement obtained by the new thickness computation approach is more accurate than that obtained by the existing thickness computation approaches.

Most existing deterministic multithreading systems are costly on pipeline parallel programs due to load imbalance. In this letter, we propose a Load-Balanced Deterministic Runtime (LBDR) for pipeline parallelism. LBDR deterministically takes some tokens from non-synchronization-intensive threads to synchronization-intensive threads. Experimental results show that LBDR outperforms the state-of-the-art design by an average of 22.5%.

This paper presents a method to reduce I/O cost in MapReduce when online analytical processing (OLAP) queries are used for data analysis. The proposed method consists of two basic ideas. First, to reduce network transmission cost, mappers are organized to receive only data necessary to perform a map task, not an entire set of input data. Second, to reduce storage consumption, only record IDs are stored for checkpointing, not the raw records. Experiments conducted with TPC-H benchmark show that the proposed method is about 40% faster than Hive, the well-known data warehouse solution for MapReduce, while reducing the size of data stored for checkpoining to about 80%.