Takaharu KAMEOKA Atsushi HASHIMOTO
This paper gives an outline of key technologies necessary for science-based agriculture. In order to design future agriculture, present agriculture should be redesigned based on the context of smart agriculture that indicates the overall form of agriculture including a social system while the present precision agriculture shows a technical form of agriculture only. Wireless Sensor Network (WSN) and the various type of optical sensors are assumed to be a basic technology of smart agriculture which intends the harmony with the economic development and sustainable agro-ecosystem. In this paper, the current state and development for the optical sensing for environment and plant are introduced.
This paper proposes a Poisson denoising method with a union of directional lapped orthogonal transforms (DirLOTs). DirLOTs are 2-D non-separable lapped orthogonal transforms with directional characteristics under the fixed-critically-subsampling, overlapping, orthonormal, symmetric, real-valued and compact-support property. In this work, DirLOTs are used to generate symmetric orthogonal discrete wavelet transforms and then a redundant dictionary as a union of unitary transforms. The multiple directional property is suitable for representing natural images which contain diagonal textures and edges. Multiple DirLOTs can overcome a disadvantage of separable wavelets in representing diagonal components. In addition to this feature, multiple DirLOTs make transform-based denoising performance better through the redundant representation. Experimental results show that the combination of the variance stabilizing transformation (VST), Stein's unbiased risk estimator-linear expansion of threshold (SURE-LET) approach and multiple DirLOTs is able to significantly improve the denoising performance.
Zijun SHA Lin HU Yuki TODO Junkai JI Shangce GAO Zheng TANG
Breast cancer is a serious disease across the world, and it is one of the largest causes of cancer death for women. The traditional diagnosis is not only time consuming but also easily affected. Hence, artificial intelligence (AI), especially neural networks, has been widely used to assist to detect cancer. However, in recent years, the computational ability of a neuron has attracted more and more attention. The main computational capacity of a neuron is located in the dendrites. In this paper, a novel neuron model with dendritic nonlinearity (NMDN) is proposed to classify breast cancer in the Wisconsin Breast Cancer Database (WBCD). In NMDN, the dendrites possess nonlinearity when realizing the excitatory synapses, inhibitory synapses, constant-1 synapses and constant-0 synapses instead of being simply weighted. Furthermore, the nonlinear interaction among the synapses on a dendrite is defined as a product of the synaptic inputs. The soma adds all of the products of the branches to produce an output. A back-propagation-based learning algorithm is introduced to train the NMDN. The performance of the NMDN is compared with classic back propagation neural networks (BPNNs). Simulation results indicate that NMDN possesses superior capability in terms of the accuracy, convergence rate, stability and area under the ROC curve (AUC). Moreover, regarding ROC, for continuum values, the existing 0-connections branches after evolving can be eliminated from the dendrite morphology to release computational load, but with no influence on the performance of classification. The results disclose that the computational ability of the neuron has been undervalued, and the proposed NMDN can be an interesting choice for medical researchers in further research.
Minjoong RIM Gyuhak YEO Seungyeob CHAE Chung G. KANG
One of the most important processes in cellular-assisted device-to-device (D2D) communications is device discovery, which decides whether two devices are located close to each other. The discovery process is performed by devices periodically transmitting discovery signals so that neighbor devices can receive them to recognize their proximate physical presence. While a fixed set of discovery parameters are used regardless of devices in most of the existing works, discovery periods are not necessarily the same for all devices, as they can be set differently depending on their channel conditions and operational environments, e.g., the mobile speeds. In this paper, we present an optimization framework to determine the discovery periods for individual devices in cellular-assisted D2D communication systems. We consider two different types of optimization problems, taking the different user velocities into account: minimizing the average number of undiscovered device pairs, and minimizing the number of discovery signal transmissions while maintaining the average number of undiscovered device pairs for each device less than a pre-specified threshold. We present analytical and simulation results to demonstrate that short discovery periods can be beneficial to high-mobility devices, while longer discovery periods are allowed for devices with lower velocities.
A renal biopsy is a procedure to get a small piece of kidney for microscopic examination. With the development of tissue sectioning and medical imaging techniques, microscope renal biopsy image sequences are consequently obtained for computer-aided diagnosis. This paper proposes a new context-based segmentation algorithm for acquired image sequence, in which an improved genetic algorithm (GA) patching method is developed to segment different size target. To guarantee the correctness of first image segmentation and facilitate the use of context information, a boundary fusion operation and a simplified scale-invariant feature transform (SIFT)-based registration are presented respectively. The experimental results show the proposed segmentation algorithm is effective and accurate for renal biopsy image sequence.
Cell voltage equalizers are necessary to ensure years of operation and maximize the chargeable/dischargeable energy of series-connected supercapacitors (SCs). A two-switch voltage equalizer using a series-resonant voltage multiplier operating in frequency-multiplied discontinuous conduction mode (DCM) is proposed for series-connected SCs in this paper. The frequency-multiplied mode virtually increases the operation frequency and hence mitigates the negative impact of the impedance mismatch of capacitors on equalization performance, allowing multi-layer ceramic capacitors (MLCCs) to be used instead of bulky and costly tantalum capacitors, the conventional approach when using voltage multipliers in equalizers. Furthermore, the DCM operation inherently provides the constant current characteristic, realizing the excessive current protection that is desirable for SCs, which experience 0V and equivalently become an equivalent short-circuit load. Experimental equalization tests were performed for eight SCs connected in series under two frequency conditions to verify the improved equalization performance at the increased virtual operation frequencies. The standard deviation of cell voltages under the higher-frequency condition was lower than that under the lower-frequency condition, demonstrating superior equalization performance at higher frequencies.
P. Pungboon PANSILA Kensaku KANOMATA Bashir AHMMAD Shigeru KUBOTA Fumihiko HIROSE
Gallium oxide is expected as a channel material for thin film transistors. In the conventional technologies, gallium oxide has been tried to be fabricated by atomic layer deposition (ALD) at high temperatures from 100--450$^{circ}$C, although the room-temperature (RT) growth has not been developed. In this work, we developed the RT ALD of gallium oxide by using a remote plasma technique. We studied trimethylgallium (TMG) adsorption and its oxidization on gallium oxide surfaces at RT by infrared absorption spectroscopy (IRAS). Based on the adsorption and oxidization characteristics, we designed the room temperature ALD of Ga$_{2}$O$_{3}$. The IRAS indicated that TMG adsorbs on the gallium oxide surface by consuming the adsorption sites of surface hydroxyl groups even at RT and the remote plasma-excited water and oxygen vapor is effective in oxidizing the TMG adsorbed surface and regeneration of the adsorption sites for TMG. We successfully prepared Ga$_{2}$O$_{3}$ films on Si substrates at RT with a growth per cycle of 0.055,nm/cycle.
Akio OHTA Chong LIU Takashi ARAI Daichi TAKEUCHI Hai ZHANG Katsunori MAKIHARA Seiichi MIYAZAKI
Ni nanodots (NDs) used as nano-scale top electrodes were formed on a 10-nm-thick Si-rich oxide (SiO$_{mathrm{x}}$)/Ni bottom electrode by exposing a 2-nm-thick Ni layer to remote H$_{2}$-plasma (H$_{2}$-RP) without external heating, and the resistance-switching behaviors of SiO$_{mathrm{x}}$ were investigated from current-voltage ( extit{I--V}) curves. Atomic force microscope (AFM) analyses confirmed the formation of electrically isolated Ni NDs as a result of surface migration and agglomeration of Ni atoms promoted by the surface recombination of H radicals. From local extit{I--V} measurements performed by contacting a single Ni ND as a top electrode with a Rh coated Si cantilever, a distinct uni-polar type resistance switching behavior was observed repeatedly despite an average contact area between the Ni ND and the SiO$_{mathrm{x}}$ as small as $sim$ 1.9 $ imes$ 10$^{-12}$cm$^{2}$. This local extit{I--V} measurement technique is quite a simple method to evaluate the size scalability of switching properties.
P. Pungboon PANSILA Kensaku KANOMATA Bashir AHMMAD Shigeru KUBOTA Fumihiko HIROSE
Nitrogen adsorption on thermally cleaned Si(100) surfaces by pure and plasma excited NH$_{3}$ is investigated by extit{in situ} IR absorption spectroscopy and ex-situ X-ray photoelectron spectroscopy with various temperatures from RT (25$^{circ}$C) to 800$^{circ}$C and with a treatment time of 5,min. The nitrogen coverage after the treatment varies according to the treatment temperature for both pure and plasma excited NH$_{3}$. In case of the pure NH$_{3}$, the nitrogen coverage is saturated as low as 0.13--0.25 mono layer (ML) while the growth of the nitride film commenced at 550$^{circ}$C. For the plasma excited NH$_{3}$, the saturation coverage was measured at 0.54,ML at RT and it remained unincreased from RT to 550$^{circ}$C. This indicates that the plasma excited NH$_{3}$ enhances the nitrogen adsorption near at RT. It is found that main species of N is Si$_{2}=$ NH in case of the plasma excited NH$_{3}$ at RT while the pure NH$_{3}$ treatment gives rise to the Si--NH$_{2}$ passivation with Si--H at RT. We discuss the mechanism of the nitrogen adsorption on Si(100) surfaces with the plasma excited NH$_{3}$ in comparison with the study on the pure NH$_{3}$ treatment.
This paper proposed patient friendly capsule endoscopy (CE) for not only screening but also treatment. Two different types of CEs with an Internet utility were investigated. The first type used magnetic navigation in the stomach and colon for screening. Magnetic navigation enabled the capsule to explore the whole of the gastrointestinal tract with less risk of missing lesions and complete the screening within the battery life. The system's design was patiently friendly as it allowed the subjects to leave the hospital after the capsule had been navigated in the stomach. The second investigated two different therapeutic robotic endoscopes. Both prototypes were driven by DC motors and controlled remotely via the internet. In addition, they were equipped with therapeutic tools and each prototype's ability with the tools was assessed. The investigation showed it was possible to remotely control both prototypes and operate therapeutic tools via the Internet. The investigation identified areas for improvement, such as size, connection speed, security of data, and the holding the capsule's position during treatment, In conclusion, both methods have the potential to make capsule endoscopy a very patient friendly procedure that can be carried out anywhere.
Keisuke MAEHATA Makoto MAEDA Naoko IYOMOTO Kenji ISHIBASHI Keisuke NAKAMURA Katsunori AOKI Koji TAKASAKI Kazuhisa MITSUDA Keiichi TANAKA
A four-pixel-array superconducting transition-edge sensor (TES) microcalorimeter with a mushroom-shaped absorber was fabricated for the energy dispersive spectroscopy performed on a transmission electron microscope. The TES consists of a bilayer of Au/Ti with either a 50-nm or 120-nm thickness. The absorber of 5.0,$mu$m thick is made from a Au layer and its stem is deposited in the center of the TES surface. A Ta$_{2}$O$_{5}$ insulating layer of 100-nm thickness is inserted between the overhang region of the absorber and the TES surface. A selected pixel of the TES microcalorimeter was operated for the detection of Np L X-rays emitted from an $^{241}$Am source. A response of the TES microcalorimeter to L X-rays was obtained by analyzing detection signal pulses with using the optimal filter method. An energy resolution was obtained to be 33,eV of the full width at half maximum value at 17.751,keV of Np L$_{eta 1}$ considering its natural width of 13.4,eV. Response to L X-rays emitted from a mixture source of $^{238}$Pu, $^{239}$Pu and $^{241}$Am was obtained by operating the selected pixel of the TES microcalorimeter. Major L X-ray peaks of progeny elements of $alpha$ decay of Pu and Am isotopes were clearly identified in the obtained energy spectrum. The experimental results demonstrated the separation of $^{241}$Am and plutonium isotopes by L X-ray spectroscopy.
Since the birth of astrophysics, astronomers have been using free-space optics to analyze light falling on Earth. In the future however, thanks to the advances in photonics and nanoscience/nanotechnology, much of the manipulation of light might be carried out using not optics but confined waveguides, or circuits, on a chip. This new generation of instruments will be not only extremely compact, but also powerful in performance because the integration enables a greater degree of multiplexing. The benefit is especially profound for space- or air-borne observatories, where size, weight, and mechanical reliability are of top priority. Recently, several groups around the world are trying to integrate ultra-wideband (UWB), low-resolution spectrometers for millimeter-submillimeter waves onto microchips, using superconducting microelectronics. The scope of this Paper is to provide a general introduction and a review of the state-of-the-art of this rapidly advancing field.
Recently, a next-generation heterodyne mixer detector---a hot electron bolometer (HEB) mixer employing a superconducting microbridge---has gradually opened up terahertz-band astronomy. The surrounding state-of-the-art technologies including fabrication processes, 4 K cryostats, cryogenic low-noise amplifiers, local oscillator sources, micromachining techniques, and spectrometers, as well as the HEB mixers, have played a valuable role in the development of super-low-noise heterodyne spectroscopy systems for the terahertz band. The current developmental status of terahertz-band HEB mixer receivers and their applications for spectroscopy and astronomy with ground-based, airborne, and satellite telescopes are presented.
To immobilize cytochrome $c$ (cyt.,$c$) on ITO electrode with keeping its direct electron transfer (DET) activity, 10-carboxydecylphosphonic acid (10-CDPA) self-assembled monolayer (SAM) film was formed on ITO electrode. After 100 times washing process with exchanging phosphate buffer saline solution in the cell to fresh one, extit{in situ} slab optical waveguide (SOWG) absorption spectral measurement proved that about 80% of cyt.,$c$ immobilized on 10-CDPA modified ITO electrode was adsorbed on ITO electrode. Additionally SOWG spectral change of cyt.,$c$ between oxidized and reduced forms was observed with setting the ITO electrode potential at 0.3 and $-$0.3,V vs. Ag/AgCl, respectively showing DET reaction between cyt.,$c$ and ITO electrode occurred. About 30% of a monolayer coverage was estimated from the coulomb amount in the surface area of oxidation and reduction peaks on cyclic voltammetry (CV) data. CV peak current maintained 84% for ITO electrode modified with 10-CDPA SAM film after 60,min continuous scan with 0.1,V/sec from 0.3 and $-$0.3,V vs. Ag/AgCl.
Nobuo SATOH Shigetaka KATORI Kei KOBAYASHI Kazumi MATSUSHIGE Hirofumi YAMADA
We have investigated both the film thickness and surface potential of organic semiconductors deposited on two kinds of electrodes by the simultaneous observation with the dynamic force microscopy (DFM)/Kelvin-probe force microscope (KFM). To clarify the interfacial properties of organic semiconductor, we fabricated samples that imitated the organic light emitting diode (OLED) structure by depositing bis [$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.
Takeshi FUKUDA Tomokazu KURABAYASHI Hikari UDAKA Nayuta FUNAKI Miho SUZUKI Donghyun YOON Asahi NAKAHARA Tetsushi SEKIGUCHI Shuichi SHOJI
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.
Kyunghoon LEE Wonjun HWANG Hyung-Jin CHOI
In recent 3GPP (3rd Generation Partnership Project) standardization meetings, D2D (Device-to-Device) discovery has been a major issue to support commercial/social services and public safety in disaster environment, and TDM (Time Division Multiplexing) based discovery channel structure is mainly considered to prevent mutual interference between D2D and cellular traffic. In this structure, D2D discovery among the same cell UEs (User Equipment) has no problem because they have the same timing source. However, LTE (Long Term Evolution) assumes an asynchronous network where two adjacent eNBs (evolved Node B) have a symbol-level timing offset. For that reason, asynchronous interference among discovery signals can appear in inter-cell D2D discovery. Therefore, channel re-use scheduling was studied previously in which neighboring cells do not use the same portion of the extended discovery channel and other non-neighboring cells re-use it. However, it still shows interference problems in small cell networks which cause substantial cellular traffic loss. Therefore, in this paper, we propose a novel discovery channel scheduling in which eNBs time-align their discovery channels from each other by sample-level. In the proposed scheme, serving eNB requests cell edge UEs to estimate NTD (Network Time Difference) between serving eNB and neighboring eNB. Then, considering multiple NTDs, eNB adjusts the sample position of its discovery channel based on a novel decision rule. We verify that the proposed scheme can match the discovery performance of a synchronous network with less cellular uplink loss.
Yen-Wen CHEN Meng-Hsien LIN Yung-Ta SU
To lengthen the operational time of mobile devices, power must be managed effectively. To achieve this objective, a Discontinuous Reception (DRX) mechanism is proposed for use in the long-term evolution (LTE) network to enable user equipment (UE) to consume power efficiently. The DRX mechanism provides parameters related to base stations such as evolved Node B (eNB) to configure and manage the transition of UEs between idle (sleep) and active states. Although these parameters can be adjusted dynamically in cooperation with the traffic scheduler, a high signaling overhead and processing load might be introduced in practical deployment if the parameters are adjusted too frequently. In this study, to examine power-saving efficiency, distinct traffic types were scheduled that were constrained by various quality of service (QoS) factors without dynamically changing the DRX parameters. The concept of burst-based scheduling is proposed, based on considering the state transitions and channel conditions of each UE, to increase power-saving efficiency while concurrently satisfying the desired QoS. Both Hypertext Transfer Protocol (HTTP) and video-stream traffic models were exhaustively simulated to examine the performance of the proposed scheme and numerous scheduling alternatives were tested to compare the proposed scheme with other schemes. The simulation results indicate that video-streaming traffic is more sensitive to the scheduling schemes than HTTP traffic. The simulation results were further analyzed in terms of traffic scheduling and parameter adjustment and the analysis results can help design future studies on power management in the LTE network.
Xiaohong YANG Mingxing XU Yufang YANG
The research reported in this paper is an attempt to elucidate the predictors of pause duration in read-aloud discourse. Through simple linear regression analysis and stepwise multiple linear regression, we examined how different factors (namely, syntactic structure, discourse hierarchy, topic structure, preboundary length, and postboundary length) influenced pause duration both separately and jointly. Results from simple regression analysis showed that discourse hierarchy, syntactic structure, topic structure, and postboundary length had significant impacts on boundary pause duration. However, when these factors were tested in a stepwise regression analysis, only discourse hierarchy, syntactic structure, and postboundary length were found to have significant impacts on boundary pause duration. The regression model that best predicted boundary pause duration in discourse context was the one that first included syntactic structure, and then included discourse hierarchy and postboundary length. This model could account for about 80% of the variance of pause duration. Tests of mediation models showed that the effects of topic structure and discourse hierarchy were significantly mediated by syntactic structure, which was most closely correlated with pause duration. These results support an integrated model combining the influence of several factors and can be applied to text-to-speech systems.
Daying SUN Weifeng SUN Qing WANG Miao YANG Shen XU Shengli LU
A new digital controller for a single-phase boost power factor correction (PFC) converter operating at a discontinuous conduction mode (DCM), is presented to achieve high input power factor over wide input voltage and load range. A method of duty cycle modulation is proposed to reduce the line harmonic distortion and improve the power factor. The loop regulation scheme is adopted to further improve the system stability and the power factor simultaneously. Meanwhile, a novel digital pulse width modulator (DPWM) based on the delay lock loop technique, is realized to improve the regulation linearity of duty cycle and reduce the regulation deviation. The single-phase DCM boost PFC converter with the proposed digital controller based on the field programmable gate array (FPGA) has been implemented. Experimental results indicate that the proposed digital controller can achieve high power factor more than 0.99 over wide input voltage and load range, the output voltage deviation is less than 3V, and the peak conversion efficiency is 96.2% in the case of a full load.