• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.8
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• pp.24-31
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• 2008

Power converters are becoming an essential block in modem mobile multimedia application. This paper presents a high performance DC-DC buck converter for mobile applications. Controller of DC-DC buck converter is designed by current-mode control method. An current-mode DC-DC converter is implemented in a standard $0.18{\mu}m$ CMOS process, and the overall die size was $1.2mm^2$. The peak efficiency was 86 % with a switching frequency of $1\sim1.5MHz$ and a maximum load current of 400mA.

• Journal of IKEEE
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• v.25 no.3
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• pp.578-583
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• 2021

This paper describes acceleration tests for reliability of semiconductors. It also describes AEC-Q100, international test standard for reliability of automotive semiconductors. Semiconductors can be used for dozens of years. So acceleration tests are essential to test potential problems over whole period of product where test time is minimized by applying intensive stresses. AEC-Q100 is a typical acceleration test in automotive semiconductors, and it is designed to find various failures in semiconductors and to analyze their causes of occurance. So it finds many problems in design and fabrication as well as it predicts lifetime and reliability of semiconductors. AEC-Q100 consists of 7 test groups such as accelerated environmental stress tests, accelerated lifetime simulation tests, package assembly integrity tests, die fabrication reliability tests, electrical verification tests, defect screening tests, and cavity package integrity tests. It has 4 grades from grade 0 to grade 3 based on operational temperature. AEC-Q101, Q102, Q103, Q104, and Q200 are applied to discrete semiconductors, optoelectronic semiconductors, sensors, multichip modules, and passive components, respectively.

• The Journal of Advanced Prosthodontics
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• v.13 no.1
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• pp.36-45
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• 2021

Purpose. To investigate the fracture resistance of monolithic CAD-CAM all-ceramic surveyed crowns with two different occlusal rest seat designs. Materials and Methods. Two maxillary first premolar were prepared for all-ceramic surveyed crowns with wide (2/3rd of buccolingual width of an unprepared tooth) or narrow (1/3rd of buccolingual width of an unprepared tooth) disto-occlusal rest seat (ORS) designs. Eighty monolithic CAD-CAM all-ceramic surveyed crowns were prepared and divided into 4 groups - Group CR, Composite resin material as a control; Group LDS, Lithium disilicate based material; Group ZIPS, zirconia-material (IPS ZirCAD); and Group ZLHT, zirconia- material (CeramillZolidht+). Crowns were cemented on an epoxy resin die with adhesive resin cement. The fracture resistance of crowns was tested with the universal machine. Univariate regression analysis was used. Results. The mean ± standard deviation of maximum failure force values varied from 3476.10 ± 285.97 N for the narrow ORS subgroup of group ZIPS to 687.89 ± 167.63 N for the wide ORS subgroup of group CR. The mean ± standard deviation of maximum force was 1075 ± 77.0 N for group CR, 1309.3 ± 283.9 N for group LDS, 3476.1 ± 285.97 N for group ZIPS, and 2666.7 ± 228.21 N for group ZLHT, with narrow occlusal rest seat design. The results of the intergroup comparison showed significant differences in fracture strength with various material groups and occlusal rest seat designs (P<.001). Conclusion. The zirconia-based all-ceramic surveyed crowns fractured at more than double the load of Lithium disilicate based crowns. The crowns with narrow base occlusal rest seat design had statistically significantly higher fracture resistance than surveyed crowns with wide occlusal rest seat design. The use of narrow occlusal rest seat design in CAD-CAM all ceramic surveyed crowns provides higher fracture resistance, and therefore narrow occlusal rest design can be used for providing esthetics with high strength.

• Korean Journal of Veterinary Service
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• v.14 no.1
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• pp.49-61
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• 1991

The present study was conducted to investigate biochemical, serologic, and pathogenic characteristic of E. rhusiopathiae isolated from the cases of acute septicemic swine erysipelas in Youngnam provinces during the period from June 1988 to September 1990. The majority of biochemical and cultural properties of E. rhusiopathiae isolated from pigs affected with acute erysipelas were identical to those of the standard strain employed. All of the 45 isolates were serotype la. All isolates were highly susceptible to penicillin G, lincomycin, cephalothin, ampicillin, erythromycin (MIC : 0.025-0.78IU or ${\mu}g$ / ml ), and moderately susceptible to oleandomycin, oxytetracycline, chloramphenicol (MIC : 0.78-25${\mu}g$ / ml ). Kanamycin and sulfadimethoxine showed no activity against the isolates(MIC : ＞400${\mu}g$ / ml ). The MICs of dihydrostreptomycin presented two distribution peaks ; of 45 strains, 5(11.1%) were resistant to dihydrostreptomycin(MIC : 400${\mu}g$ / ml ). All of 5 selected isolates were pathogenic for mite and $LD_{50}$ was $3.7{\times}10^3$viable cells. Mice immunized subcutaneously with live vaccine did not die after challenge to virulent isolates of E. rhusiopathiae.

• International Journal of Precision Engineering and Manufacturing
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• v.4 no.2
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• pp.49-56
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• 2003

As semi-solid forging (SSF) is compared with conventional casting such as gravity die-casting and squeeze casting, the product without inner defects can be obtained from semi-solid forming and globular microstructure as well. Generally, SSF consists of reheating, forging, and ejecting processes. In the reheating process, the materials are heated up to the temperature between the solidus and liquidus line at which the materials exists in the form of liquid-solid mixture. The process variables such as reheating time, reheating temperature, reheating holding time, and induction heating power has large effect on the quality of the reheated billets. It is difficult to consider all the variables at the same time for predicting the quality. In this paper, Taguchi method, regression analysis and neural network were applied to analyze the relationship between processing conditions and solid fraction. A356 alloy was used for the present study, and the learning data were extracted from the reheating experiments. Results by neural network were in good agreement with those by experiment. Polynominal regression analysis was formulated using the test data from neural network. Optimum processing condition was calculated to minimize the grain size and solid fraction standard deviation or to maximize the specimen temperature average. Discussion is given about reheating process of row material and results are presented with regard to accurate process variables fur proper solid fraction, specimen temperature and grain size.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.6
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• pp.559-565
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• 2010

In this paper, we present a transformation method of source code from a POSIX (Portable Operating System Interface) based source code into an OSEK/VDX (Offene Systeme und deren Schnittstellen fur die Elektronik in Kraftfahrzeugen/Vehicle Distributed eXecutive) source code. As the electronic parts of automobile systems increase, the use of embedded software in automobile systems is also growing. Accordingly, many electronic systems are designed in automobile system with OSEK/VDX. Otherwise, one of the major problems of embedded software would be portability to other OS's. To enhance the portability and interoperability of embedded software, we propose a source code transformation method from POSIX to OSEK/VDX based on API (Application Programming Interface) translation method. Considering the characteristics of the OSEK/VDX which uses OIL (OSEK/VDX Implementation Language) standard, transformation process is performed with source code transformation and OIL code generation. For the validity of the proposed method, the transformation experiment is given using Micro-C OS II and OSEK/VDX with XC167CI micro-controller.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.10
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• pp.186-194
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• 1996

The SliM (sliding memory plane) array processor has been proposed to alleviate disadvantages of existing mesh-connected SIMD(single instruction stream- multiple data streams) array processors, such as the inter-PE(processing element) communication overhead, the data I/O overhead and complicated interconnections. This paper presents the deisgn and implementation of SliM image processor ASIC (application specific integrated circuit) chip consisting of mesh connected 5 X 5 PE. The PE architecture implemented here is quite different from the originally proposed PE. We have performed the front-end design, such as VHDL (VHSIC hardware description language)modeling, logic synthesis and simulation, and have doen the back-end design procedure. The SliM ASIC chip used the VTI 0.8$\mu$m standard cell library (v8r4.4) has 55,255 gates and twenty-five 128 X 9 bit SRAM modules. The chip has the 326.71 X 313.24mil$^{2}$ die size and is packed using the 144 pin MQFP. The chip operates perfectly at 25 MHz and gives 625 MIPS. For performance evaluation, we developed parallel algorithms and the performance results showed improvement compared with existing image processors.

• ETRI Journal
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• v.29 no.4
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• pp.421-429
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• 2007

This paper presents a direct-conversion CMOS transceiver for fully digital DS-UWB systems. The transceiver includes all of the radio building blocks, such as a T/R switch, a low noise amplifier, an I/Q demodulator, a low pass filter, a variable gain amplifier as a receiver, the same receiver blocks as a transmitter including a phase-locked loop (PLL), and a voltage controlled oscillator (VCO). A single-ended-to-differential converter is implemented in the down-conversion mixer and a differential-to-single-ended converter is implemented in the driver amplifier stage. The chip is fabricated on a 9.0 $mm^2$ die using standard 0.18 ${\mu}m$ CMOS technology and a 64-pin MicroLead Frame package. Experimental results show the total current consumption is 143 mA including the PLL and VCO. The chip has a 3.5 dB receiver gain flatness at the 660 MHz bandwidth. These results indicate that the architecture and circuits are adaptable to the implementation of a wideband, low-power, and high-speed wireless personal area network.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.15
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• pp.6397-6400
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• 2015

Cervical cancer is the second most common gynecological malignancy worldwide. According to HPV Information Centre, Spain (Aug'2014), in India approximately 1,22,844 women are diagnosed with the disease every year and of them 67,477 die due to the disease. CaCx is said to be mediated by HPV but recent data published reveal the role of Oxidative Stress in different Cancers. Arsenic is also one of the agents for causing Oxidative Stress. Arsenic has been linked with different types of cancer. Arsenic is considered responsible for generation of free radicals and eventually for apoptosis. Early diagnosis of CaCx is presently a matter of concern and clinical presentation in advanced stages become difficult for complete clinical response. For determination of oxidative stress, Malondialdehyde (MDA) was taken as an identifier and arsenic estimation was performed with the help of Atomic Absorption Spectrometer (AAS). RBC count and Haemoglobin levels were performed according to standard protocol. MDA was in direct proportion with arsenic concentration and inversely proportional to RBC and Haemoglobin in CaCx patients. Arsenic is one of the major causative agents for oxidative stress and hence may be a risk factor leading to cancer including CaCx.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.12
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• pp.115-125
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• 2003

The design methodology of plastic injection molding die has been gradually moved from two-dimensional line drawings to three-dimensional solid models. The 3D design gives many benefits, a few of which are: ease of design change, data associativity from concept design to final assembly. In the paper represented is the implementation of a program which automatically generates 3D mold-bases and cooling-lines, conforming to given geometric constraints. It utilized a commercial CAD software and the related API(application program interface) libraries. We constructed a DB(database) of typical mold-bases assembled from standard parts, from which the geometry (position & dimension) of a mold-base and composed parts can be automatical]y determined by a few key parameters. Also we classified cooling lines into several typical types and constructed a DB, from which the position of cooling lines is automatically determined. The research is expected not only to simplify construction of a 3D mold-base model including cooling lines but also to reduce design efforts, by way of databases and automatized determination of geometric dimensions.