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Electrochromic technologies have recently attracted attention due to their energy-saving performance for reducing green gas emissions. The materials design and preparation of electrochromic materials with sufficient microstructure and crystallographic features for suitable ion intercalation/deintercalation are essential for high performance and efficiency. In the present work, nanostructured amorphous tungsten trioxide (WO

This paper presents the effects of aperture diameter on image blur of complementary metal–oxide–semiconductor (CMOS) image sensor with pixel apertures for depth extraction. In a conventional camera system, the aperture is located at the camera lens. However, in the proposed camera system, the aperture is located on the photodiode. The patterns in the pixel array of the fabricated CIS are composed of blue, red, and white pixels, as well as pixel apertures. The pixel apertures are formed by a metal pattern in the white pixels and designed using a metal layer in the CIS process. The focused and defocused images are simultaneously obtained using white pixels with and without the pixel apertures. The focused image can be used as a reference image to extract depth information for 3-D imaging. The sensor was designed and fabricated using the 0.11- $\mu \text{m}$ CIS process. The image blur as a function of the aperture diameter was measured using the fabricated sensor. In addition, the effects of the $F$ -number of the camera lens, which is defined as the ratio of focal length to the diameter of the camera lens, and variation in the output of the CIS with the angle of incidence were investigated.

Latency, error vector magnitude (EVM) and compression ratio (CR) are performance evaluation factors of IQ data compression. The purposes of IQ data compression are to minimize the latency, EVM and to maximize the CR. However, there is a tradeoff between them. In this paper, based on the evaluation factors, we analyze existing IQ data compression schemes and propose a simple and efficient method from the analyzed results. The proposed method is composed of partial cyclic prefix and cyclic suffix insertion, $K/L$ decimation, low-order bits removal, and partial Huffman code. It presents the techniques to minimize the EVM caused by $K/L$ decimation and to optimize the number of removable low bits and available Huffman encoding bits based on the average signal power and desired EVM. The proposed method can achieve the CR of 4 times or more in about 2% EVM for the LTE downlink and uplink. The simulation results show that the proposed method is applicable to SIMO and MIMO environments.

In this study, a process optimization methodology was proposed to minimize the alignment error between contact pads during the direct wafer-to-wafer bonding process. The reason of occurring alignment error in the conventional wafer-to- wafer bonding process is that there is a deformation difference between upper wafer and lower wafer during the bonding process. This deformation difference is occurred by asymmetric pressure head for initiating the bond, wafer anisotropy, and gravitational influence during bonding. In this study, a FEA (Finite Element Analysis) model which can simulate the WtW bonding for optimization of bonding process was developed. In order to define the bonding force acting between the wafers during bonding, characteristics of wafer surface were analyzed by molecular dynamics analysis using SiCN surface model that is plasma-treated with oxide. The bonding force with respect to the distance obtained by analysis were implemented as subroutine and applied to the wafer bonding simulation model in ABAQUS, which is commercial FEA software. The simulation model was verified through comparing bonding propagation distance and alignment error measurement results. We conducted the process optimization to minimize the alignment error using our FEA model. As a result of optimization, wafer-to-wafer bonding process that has an alignment error about tens nm level was proposed.

The adsorption capability of eosin Y as a model anionic dye on natural halloysite nanotubes (HNTs) and sulfuric acid-treated HNTs as a function of acid treatment time (1 h, 3 h, and 5 h) was examined. Scanning electron microscopy revealed that natural HNTs had a very uniform surface, whereas acid-treated HNTs had a rough surface with structural defects, which increased with acid treatment time. The total specific pore volume and total surface area of the acid-treated HNTs increased due to formation of nanopores in the HNTs via dissolution of the inner AlO6 octahedral layer. With acid treatment, the surface ξ—potentials were positively shifted from −42.9 mV (for the natural HNTs) to −1.9, −3.0, and +1.2 mV after 1, 3, and 5 h, respectively. The adsorption amount (qe) of eosin Y on natural HNTs and the three acid-treated HNTs was 2.3, 125.5, 118.9, and 118.9 mg g−1, respectively, implying that the adsorption capacity of acid-treated HNTs is ~50 times higher than that of natural HNTs. In this study, we clearly demonstrated that acid-treated HNTs can be used as highly efficient nanomaterials for removal of dyes from wastewater containing anionic dyes.

CMOS image sensor (CIS) is used in various applications such as surveillance cameras, automobile cameras, mobile phones and digital single lens reflex (DSLR). The photodetectors used in the CIS are p-n junction photodiodes, pinned photodiodes, MOSFET-type photodetectors, and bipolar junction transistor-type photodetectors. A CMOS active pixel sensor (APS) with adjustable sensitivity is presented which uses MOSFET-type photodetector with a built-in transfer gate. The sensitivity of the APS using the MOSFET-type photodetector is much higher than that of the APS using the pn junction photodiode, since the MOSFET-type photodetector is composed of a floating-gate tied to an n-well and the photocurrent is amplified by the MOSFET. Although the APS using conventional MOSFET-type photodetector cannot control the current flowing through the channel, the APS using MOSFET-type photodetector with a built-in transfer gate can control the photocurrent by adjusting the pulse level of the transfer gate. Since the transfer gate controls the amount of electric charge that is transferred from the drain of the MOSFET to the integration node, the sensitivity of the APS can be adjusted by controlling the pulse level of the transfer gate. Using the high sensitivity characteristic of MOSFETtype photodetector and the function of transfer gate, the APS maintains high sensitivity under low intensity of illumination and adjusts to low sensitivity under high intensity of illumination. These results might be useful for extending the dynamic range of the APS using the MOSFET-type photodetector. The CMOS APS was designed and fabricated using 2-poly 4-metal 0.35 μm standard process and its performance was evaluated.

A simplified soft demapper for non-square quadrature amplitude modulation (QAM) provided by fifth generation of high-speed data-over-cable systems (DOCSIS 3.1) is proposed. By using the geometric tendency of the non-square QAM constellation and “fold-and-overlap” approach, the non-linear log likelihood ratio (LLR) equation based on the max-log maximum a posteriori (MAP) algorithm can be approximated to linear equations. With this approximation, the proposed method can be applied to high-order non-square QAM, up to 8192 QAM, with negligible bit error rate performance degradation under additive white Gaussian noise and multipath flat-fading channels. Computational complexity is reduced by at least 93% compared to the LLR calculation based on the max-log MAP algorithm.

Data over cable service interface specification 3.1 (DOCSIS 3.1) is released to provide multi-gigabit data service in hybrid fiber coaxial (HFC) networks. To support the data rate of DOCSIS 3.1 uplink, the low density parity check (LDPC) decoding processing speed is required as corresponding to the data rate. We implement the LDPC encoder and decoder based on the DOCSIS 3.1 uplink and verify them by the laboratory test. The results of the laboratory test show that the implemented LDPC encoder and decoder conforms to the DOCSIS 3.1 uplink.

A CMOS image sensor with off-center circular apertures for two-dimensional (2D) and three-dimensional (3D) imaging was fabricated, and its performance was evaluated, including the results of 2D and 3D images. The pixel size, based on a four-transistor active pixel sensor with a pinned photodiode, is 2.8 μm × 2.8 μm. Disparate images as well as focused images for depth calculation can be obtained using the designed pixel pattern. The pixel pattern is composed of one white subpixel with a left-offset circular aperture, a blue pixel, a red pixel, and another white subpixel with a right-offset circular aperture. The proposed technique was verified by simulation and measurement results using a point light source. In addition, the depth image was implemented by calculating the depth information from the 2D images.

A demagnetization fault in a permanent-magnet synchronous machine (PMSM) degrades performance and energy efficiency. The demagnetization fault causes flux-density difference and changes the PMSM inductances. Such varying parameters make it difficult to detect and diagnose the exact severity of a demagnetization fault. In this paper, we suggest a use of structural analysis of the PMSMs to diagnose the demagnetization fault. We can calculate varying inductances and consider the magnetic saturation effect with varying flux linkages of the machine. Combination of the proposed technique with the least-square (LS) method shows better results than the conventional methods in the estimation of flux linkages in the PMSMs with the demagnetization fault. Experimental results demonstrate that the proposed method works well both in the tracking of varying inductances and the diagnosis of the demagnetization fault.

Graphene oxide (GO) was synthesized by using a “top-down” approach with the Hummers method; 2-dimensional (2-D) GO sheets were obtained starting from bulk graphite. The GO sheets were cut into nanoparticles by using ultrasonic dispersion in deionized water. The GO nanoparticle solution was deposited on fluorine-doped tin-oxide glass by using electrophoretic deposition (EPD). We applied the deposition current and voltage by using the results of cyclic voltammetry. The EPD process was monitored during the deposition times by using real-time chronoamperometery. The deposited GO films showed over 80% transmittance at 550 nm in spite of the composite structure consisting of porous particles and 2-D sheets. We prepared GO-based composite structures as counter electrodes for dye-sensitized solar cells. From the results of the electrochemical impedance spectroscopy, the electron transfer in the composite counter electrode was better than that of the graphite or the platinum. Also, the energy conversion efficiency was enhanced to 6.02% by using the suggested GO counter electrodes.

This study aims at developing and evaluating reconstitutable dry suspension (RDS) improved for dissolution rate, oral absorption, and convenience of use of poorly water-soluble celecoxib (CXB). Micro-sized CXB particle was used to manufacture nanosuspension by using bead milling and then RDS was made by spray-drying the nanosuspension with effective resuspension agent, dextrin. The redispersibility, morphology, particle size, crystallinity, stability, dissolution, and pharmacokinetic profile of the RDS were evaluated. RDS was effectively reconstituted into nanoparticles in 775.8 &plusmn, 11.6 nm. It was confirmed that CXB particles are reduced into needle-shape ones in size after the bead-milling process, and the description of CXB was the same in the reconstituted suspension. Through the CXB crystallinity study using differential scanning calorimetry (DSC) and XRD analysis, it was identified that CXB has the CXB active pharmaceutical ingredient (API)&rsquo, s original crystallinity after the bead milling and spray-drying process. In vitro dissolution of RDS was higher than that of CXB powder (93% versus 28% dissolution at 30 min). Furthermore, RDS formulation resulted in 5.7 and 6.3-fold higher area under the curve (AUC&infin, ) and peak concentration (Cmax) of CXB compared to after oral administration of CXB powder in rats. Collectively, our results suggest that the RDS may be a potential oral dosage formulation for CXB to improve its bioavailability and patient compliance.

Recently, HFC (hybrid fiber cable) has been widely used due to the demand for economical and efficient digital services. HFC can be used for an integrated digital service broadband network access technology, through the photoelectric conversion process to achieve data transmission between different devices and equipment. Therefore, RoIP (Radio Over IP) technology for two-way communication is revealed without changing the original system hardware structure. RoIP is a technology that converts radio frequency signal generated at a transmitting end into digital signal and transmits it using an optical IP network. However, during the signal conversion process, a large amount of data generated needs to be compressed to achieve efficient data transmission. In this paper, we reduce the amount of data by combining linear predictive coding techniques, which is widely used in speech signal processing, with nonlinear quantization coding. By using this method, RF signals can be transmitted efficiently. We measured the compression ratio and the magnitude of the error vector representing the degree of signal damage during the compression process and compared it with previous experimental results to verify the availability of these schemes.

The effects of O2 plasma post-treatment on the electrical behavior of Ga-doped ZnO (GZO) films were characterized. GZO films were spin-coated onto glass and post-treated in an O2 plasma at a 0- to 100-W radio-frequency (RF) power and a 0- to 60-s process times in a capacitively-coupled plasma system. Atomic force microscopy, X-ray diffraction, Hall, UV-Vis spectroscopy, photoluminescence, and photocurrent measurements were used to study the influence of the O2 plasma post-treatment on the surface morphological, electrical, and optical properties of the GZO films. With increasing RF power during the O2 plasma post-treatment, the electrical properties of the GZO films improved significantly. The carrier concentration of the GZO films increased by a factor of approximately 52 from 5.89 × 1017 to 3.08 × 1019 cm -3 for a 30-s O2 plasma exposure at 100-W RF power. The electrical improvement was attributed to the GZO films’ high crystallinity, caused by the O2 plasma post-treatment reducing the number of oxygen defects. The plasma treatment had little effect on the transmittance of the GZO films. The optical band gap of the film increased with increasing RF power. An enhanced UV photocurrent was obtained for the GZO film after a 30-s O2 plasma post-treatment at a 100-W RF power, and the recovery was slow.

Glucose in the blood is generally measured by electrochemical method using glucose oxidase (GOx) which acts as enzymes and reduced graphene oxide (rGO) composite. The rGO, which has low dispersibility, reduces the sensing capability of sensors. In order to solve this problem, the rGO electrodes with the addition of polyvinylpyrrolidone (PVP) have been reported. However, rGO with low electrical conductivity and mobility is not compatible to the electrochemical system. In this study, graphene with excellent electrical properties was added to PVP protected rGO. The rGO was synthesized using a Hummer and Offeman's method. Graphene was synthesized using chemical vapor deposition (CVD) with a Cu catalyst. Platinum (Pt) electrodes, Ag/AgCl, and PVP protected rGO were used as working electrode, reference electrode, and counter electrode, respectively. Surface morphology and structural properties of graphene were analyzed using atomic force microscopy (AFM), Raman spectroscopy, and Fourier transform infrared spectroscopy (FT-IR). Cyclic voltametry (CV) and I-V probe station were used to analyze the performance of the electrodes. Glucose concentration was systematically varied and the reduction current was monitored using I-V probe station.

Summary Background Information on the natural duration of carbapenem-resistant Enterobacteriaceae (CRE) carriage and factors associated with persistence of carriage is limited. Aim To evaluate the clinical variables associated with persistent carriage of Klebsiella pneumoniae carbapenemase (KPC)-producing CRE. Methods Data for patients admitted between June 2015 and December 2016 who were identified as KPC-producing CRE carriers by either rectal swabs or clinical cultures were reviewed retrospectively. Patients with follow-up culture data for three months after initial acquisition were included. Regression models were used to evaluate the clinical variables associated with persistence of carriage. Findings Of the 100 eligible patients, 50 patients (50%) experienced spontaneous decolonization within three months. Among the 50 patients (50%) who remained culture positive after three months, 26 patients carried KPC-producing CRE after six months. Multi-variable analysis revealed that re-admission [adjusted odds ratio (aOR) 9.96; 95% confidence interval (CI) 1.13–87.98; P=0.039], duration of hospitalization (aOR 1.03; 95% CI 1.01–1.05; P=0.003), positive clinical culture (aOR 6.26; 95% CI 1.28–30.54; P=0.023) and carbapenem use (OR 9.15; 95% CI 1.85–45.27; P=0.007) were predictive for persistent carriage after six months. Conclusion The results suggest that patients with KPC-producing CRE in clinical specimens who are using carbapenem, particularly those with multiple and prolonged hospitalizations, are more likely to remain carriers after six months of initial acquisition. This information is useful for coordinating strategies for pre-emptive isolation by predicting the CRE carriage status appropriately, and ensuring active surveillance through risk factor stratification.

In this paper, we propose an efficient FFO(fractional frequency offset) estimation method for OFDM systems with RP(Roll-off period). RP is used to transmit more subcarriers in a limited bandwidth. Because neighboring OFDM symbols overlap in RP region, RP makes noises in CP(cyclic prefix) and degrades FFO estimation when Beek's method is used. The proposed method estimates FFO based on the Beek's method by detecting and eliminating RP from CP. We showed the test results of RP detection and explained the proposed FFO estimation.

A sufficiently intense electromagnetic wave, incident into a plasma, can decay into two electron plasma waves near quarter critical density layer of the plasma. This two-plasmon decay instability has been a hot topic mainly due to relevance to laser fusion in that the instability produces hot electrons causing a preheat problem. It has been known that configuration of wave vectors of the three waves involved in the instability is described by a hyperbola. However, recently there appeared a theoretical result that above a certain temperature (depending on density of the plasma) the configuration of waves should be described by a lemniscate rather than by a hyperbola. 1, 2 Thus the combined hyperbolalemniscate curve should be used in describing the configuration.

In this paper, we propose Low Energy Service Discovery (LESD) protocol for common discovery mode of IEEE 802.15.8 Peer Aware Communications (PAC). In order to minimize power consumption, Basic Repetition Block (BRB) is defined. Device is able to select operating mode and synchronize other devices through it. Proposed MAC procedure is Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) based on overhearing technique. Even if device has not been received response signal since transmitted request signal, it is able to discover other devices of same group through the overhearing technique. IEEE 802.15.8 PAC has required that performances of common discovery mode are presented about discovered devices during the simulation time, discovery latency and average power consumption. By considering the number of devices per group and channel environment, two scenarios are evaluated through system level simulation and the simulation results of proposed scheme are compared with CSMA/CA in same 논문 14-39B-05-01 The Journal of Korea Information and Communications Society '14-05 Vol.39B No.05 http://dx.doi.org/10.7840/kics.2014.39B.5.251 251 ※ 본 연구는 지식경제부 “초절전 센서네트워크 핵심기술개발” 과제에 의해 수행되었습니다. First Author : Chungnam National University Department of Information and communication, jw_lee@cnu.ac.kr, 학생회원 ° Corresponding Author : Chungnam National University Department of Information and communication, jmahn@cnu.ac.kr, 종신회원 * Electronics and Telecommunications Research Institute Department of USN/IoT Convergence research, kh.lee@etri.re.kr, tjpark@etri.re.kr, 준회원 논문번호:KICS2013-11-500, Received November 18, 2013; Revised April 16, 2014; Accepted May 9, 2014 The Journal of Korea Information and Communications Society '14-05 Vol.39B No.05 252 simulation conditions. As a result, proposed scheme is able to get high energy efficiency of devices as well as increase the number of discovered devices during simulation time when the longer the number of devices is distributed over a limited area.

This paper presents the effects of offset pixel aperture width on the performance of monochrome (MONO) CMOS image sensors (CISs) for a three-dimensional image sensor. Using a technique to integrate the offset pixel aperture (OPA) inside each pixel, the depth information can be acquired using a disparity from OPA patterns. The OPA is classified into two pattern types: Left-offset pixel aperture (LOPA) and right-offset pixel aperture (ROPA). These OPAs are divided into odd and even rows and integrated in a pixel array. To analyze the correlation between the OPA width and the sensor characteristics, experiments were conducted by configuring the test elements group (TEG) regions. The OPA width of the TEG region for the measurement varied in the range of 0.3&ndash, 0.5 &mu, m. As the aperture width decreased, the disparity of the image increased, while the sensitivity decreased. It is possible to acquire depth information by the disparity obtained from the proposed MONO CIS using the OPA technique without an external light source. Therefore, the proposed MONO CIS with OPA could easily be applied to miniaturized devices. The proposed MONO CIS was designed and manufactured using the 0.11 &mu, m CIS process.

In this paper, we propose an averaging pixel current adjustment technique for reducing fixed pattern noise (FPN) in the bolometer-type uncooled infrared image sensor. The averaging pixel current adjustment technique is composed of active pixel, reference pixel, and calibration circuit. Polysilicon resistors were used in each active pixel and reference pixel. Resistance deviation among active pixels integrated with the same resistance value cause FPN. The principle of the averaging pixel current adjustment technique for removing FPN is based on the subtraction of dark current of the active pixel from the dark current of the reference pixel. The subtracted current is converted into the voltage, which contains pixel calibration information. The calibration circuit is used to adjust the calibration current. After calibration, the nano-ampere current is output with small deviation. The proposed averaging pixel current adjustment technique is implemented by a chip composed of a pixel array, a calibration circuit, average current generators, and readout circuits. The chip was fabricated using a standard 0.35 &mu, m CMOS process and its performance was evaluated.