• ETRI Journal
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• 제29권3호
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• pp.371-380
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• 2007

This paper proposes a new automatic compensation network (ACN) for a system-on-chip (SoC) transceiver. We built a 5 GHz low noise amplifier (LNA) with an on-chip ACN using 0.18 ${\mu}m$ SiGe technology. This network is extremely useful for today's radio frequency (RF) integrated circuit devices in a complete RF transceiver environment. The network comprises an RF design-for-testability (DFT) circuit, capacitor mirror banks, and a digital signal processor. The RF DFT circuit consists of a test amplifier and RF peak detectors. The RF DFT circuit helps the network to provide DC output voltages, which makes the compensation network automatic. The proposed technique utilizes output DC voltage measurements and these measured values are translated into the LNA specifications such as input impedance, gain, and noise figure using the developed mathematical equations. The ACN automatically adjusts the performance of the 5 GHz LNA with the processor in the SoC transceiver when the LNA goes out of the normal range of operation. The ACN compensates abnormal operation due to unusual thermal variation or unusual process variation. The ACN is simple, inexpensive and suitable for a complete RF transceiver environment.

• 무역상무연구
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• 제26권
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• pp.203-223
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• 2005

Many international transactions involve the use of security devices, commonly referred to as "guarantees", "bonds", or "standby credits", designed to protect one of the parties from a breach by its counter-party. These security mechanisms may be provided by banks, insurance companies, specialized surety companies, or other financial service firms. Although some legal systems distinguish between "guarantees", "bonds", and "indemnities", these terms are often used as synonyms in the everyday language of international traders. It may therefore be necessary to examine the particular characteristics and nature of the guarantee obligation in order to properly classify the guarantee. Two main categories of guarantee are demand and suretyship. Under a demand guarantee, the guarantor must pay on first demand by the beneficiary. The beneficiary only has to demand payment under the guarantee - there is no need to prove that the principal has actually defaulted on a contractual obligation. Under a suretyship or conditional guarantee, the obligation of the guarantor is triggered by the actual default or contractual breach of the principal, as evidenced in a document such as a court judgement or arbitral award against the principal. Guarantees have been widely used in the international business transactions. Main uses of guarantees are as follows : Performance Bonds/Guarantees, Bid(or Tender) Bonds/Guarantees, Advance Payment or Repayment Bonds/Guarantees, Retention Bonds/Guarantees, Maintenance(or Warranty) Bonds/Guarantees etc.

• 조명전기설비학회논문지
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• 제26권12호
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• pp.28-36
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• 2012

Augmentation of existing EHV substations located in hilly terrain and at high altitude require many different considerations as compared to substations located in plain areas and at lower altitude. Owing to high altitude and steep terrain, meticulous engineering and preparations are required, considering the actual available space at the existing substation. Historical fault events too must be considered to enhance reliability and performance of the substation equipment. This paper proposes ways to augment the existing 2 banks of 20MVA, 220/66kV power transformers ($3{\times}6.67MVA$, single-phase) to $2{\times}50$/63MVA, 220/66kV power transformers to meet continuously increasing demand of the capital city over the next 20 years. Upgrading and augmentation of existing substations, especially the main transformers and associated equipment, require replacement with minimum or no disturbance to the existing power supply system. Considerations should also be made during engineering and design, the operational flexibilities, maintenance aspects, future expandability and value addition, in terms of reliability and space usage of the existing substation.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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• pp.433-442
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• 1993

Coolstore air relative humidity (RH) is an important factor affecting the quality of horticultural products, particularly via product moisture loss. RH also has an important effect on the performance of the refrigeration evaporators and can affect the strength of paper-based packaging materials. In a large New Zealand apple coolstore, RH increased from about 75% early in season to 90% at the end, as activities in the coolstore and external conditions changed. A steady-state analysis of sensible and latent heat entry and heat removal during four typical operational periods over the season was carried out. Predicted RH was in good agreement with measured dat. For the coolstore studied, evaporator surface area and the occurrence of pre-cooling within the coolstore were the design and operational factors having greatest effect on RH. Door protection and management, and floor insulation were the next more significant factors. The method of analysis has more general application and ould be used in a variety of situations so that design for optimum RH can be performed systematically.

• The Journal of the Acoustical Society of Korea
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• 제20권4E호
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• pp.52-60
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• 2001

This paper describes real time implementation of subband sound localization system on a floating-point DSP TI TMS320C31. The system determines two dimensional location of an active speaker in a closed room environment with real noise presents. The system consists of an two microphone array connected to TI DSP hosted by PC. The implemented sound localization algorithm is Subband CPSP which is an improved version of traditional CPSP (Cross-Power Spectrum Phase) method. The algorithm first split the input speech signal into arbitrary number of subband using subband filter banks and calculate the CPSP in each subband. It then averages out the CPSP results on each subband and compute a source location estimate. The proposed algorithm has an advantage over CPSP such that it minimize the overall estimation error in source location by limiting the specific band dominant noise to that subband. As a result, it makes possible to set up a robust real time sound localization system. For real time simulation, the input speech is captured using two microphone and digitized by the DSP at sampling rate 8192 hz, 16 bit/sample. The source location is then estimated at once per second to satisfy real-time computational constraints. The performance of the proposed system is confirmed by several real time simulation of the speech at a distance of 1m, 2m, 3m with various speech source locations and it shows over 5% accuracy improvement for the source location estimation.

• 의학교육논단
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• 제16권1호
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• pp.11-15
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• 2014

A number of medical schools in Korea have been using computer-based testing (CBT) for evaluating their students' scientific and/or clinical performance since the early 1990s. Introducing CBT to medical education would have several advantages: first, presenting figures and audio-video files of clinical content is simple with CBT, making it possible to evaluate medical students' competency with navigating more realistic clinical situations at minimum cost; second, CBT enables automatic item analysis and score reporting. To establish CBT, constructing an item bank with item parameters such as difficulty or discriminating parameters will be needed. To select more psychometrically sound items, analysis of the items according to item response theory is necessary. CBT has already been introduced in high stakes tests like the United States Medical Licensing Examination and the Medical Council of Canada Qualifying Examination. The National Health Personnel Examination Board in Korea is also planning to introduce a CBT-based version of the National Medical Examination soon. Thus all medical schools in Korea will need to introduce CBT and construct item banks to prepare their students for their licensing examinations and to measure the students' competency more accurately.

• ETRI Journal
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• 제35권4호
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• pp.697-705
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• 2013

Emerging trends in the area of digital very large scale integration (VLSI) signal processing can lead to a reduction in the cost of the cochlear implant. Digital signal processing algorithms are repetitively used in speech processors for filtering and encoding operations. The critical paths in these algorithms limit the performance of the speech processors. These algorithms must be transformed to accommodate processors designed to be high speed and have less area and low power. This can be realized by basing the design of the auditory filter banks for the processors on digital VLSI signal processing concepts. By applying a folding algorithm to the second-order digital gammatone filter (GTF), the number of multipliers is reduced from five to one and the number of adders is reduced from three to one, without changing the characteristics of the filter. Folded second-order filter sections are cascaded with three similar structures to realize the eighth-order digital GTF whose response is a close match to the human cochlea response. The silicon area is reduced from twenty to four multipliers and from twelve to four adders by using the folding architecture.

• 재무관리연구
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• 제16권1호
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• pp.283-309
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• 1999

본 연구에서는 최근에 투입과 산출관계가 복잡한 비영리기관의 운영효율성을 평가하는데 많이 적용되고 있는 DEA분식기법을 이용하여 국내일반은행의 생산성을 상대적 개념에서 측정하고, 은행감독원에 의한 경영평가와 금융감독위원회의 은행퇴출평가 결과를 비교하여 봄으로서 평가결과가 타당성이 있는지 여부를 알아보았다. 금융감독위원회의 평가는 수익성, 건전성, 유동성, 내부유보 등 비율분석에 의한 평가와 BIS비율 등을 고려하여 평가해 왔기 때문에 다산출물 대 다투입물이 상호작용하는 것을 무시하고 있다는 것으로 볼 수 있다. 그리고 은행감독원의 평가와 DEA기법에 의한 경영효율성 간에는 상당한 차이가 있는 것으로 드러났다. 본 연구 분석결과로는 1995년도 효율성 값이 하위 5개 은행은 국민은행, 충북은행, 광주은행, 경남은행, 평화은행이며, 1996년도 효율성 값이 하위 5개 은행은 광주은행, 제주은행, 동남은행, 전북은행, 국민은행, 1997년도의 효율성 값이 하위 5개 은행은 대동은행, 광주은행, 충청은행, 충북은행, 전북은행으로 분석되었다. 퇴출은행 5개중 1996년도에 동남은행, 1997년도에 대동은행, 충청은행만이 효율성 값이 하위 5위안에 포함되어 본 연구의 분석결과와 다소 상이한 결과가 분석되었다. 그리고 DEA 분석모형에 의하면 비율분석에서는 점검할 수 없는 은행의 상대적 경영효율성을 분석한 결과가 금융당국의 평가결과와 다소 일치한 점도 있으나 운영효율성 측면에서 퇴출대상은행이 효율성이 높은 은행으로 평가되어 금융감독위원회가 결정한 퇴출대상은행과 DEA 분석결과와는 상이한 결과가 도출되었다.

• 한국통신학회논문지
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• 제27권7C호
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• pp.704-711
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• 2002

본 논문에서는 케이블 모뎀을 위한 DFE(Decision Feedback Equalizer) 구조의 blind 등화기를 설계하였다. 변복조 방식은 64/256 QAM이며 채널 적응 알고리즘으로는 제안한 MMA(Multi-Modulus Algorithm)와 LMS (Least Mean Square) 알고리즘을 같이 사용하였다. MMA 알고리즘과 DFE 구조를 가진 등화기는 본 논문에서 처음 제안한다. 기존의 MMA 등화기는 두 개의 FIR 필터를 사용하여 두 개의 탭 계수를 갱신하였으나, 본 논문에서 제안하는 MMA 알고리즘은 하나의 탭 계수 갱신만으로 채널 등화가 가능하도록 제안하였으며, DFE 구조에 적용하여 두 개의 DFE 필터를 사용하여 채널 적응 능력을 높히고 탭 수를 줄였다. 0.35 $\mu\textrm{m}$ standard cell library를 이용하여 ASIC 칩을 설계하였다. 설계한 등화기는 약 16만개의 게이트 수와 8 MHz의 동작속도를 보였으며 데이터 전송 속도는 64Mbps까지 지원한다.

• ETRI Journal
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• 제40권6호
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• pp.759-773
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• 2018

Uncore components such as on-chip memory systems and on-chip interconnects consume a large amount of energy in emerging embedded applications. Few studies have focused on next-generation analytical models for future chip-multiprocessors (CMPs) that simultaneously consider the impacts of the power consumption of core and uncore components. In this paper, we propose a convex-optimization approach to design heterogeneous uncore architectures for embedded CMPs. Our convex approach optimizes the number and placement of memory banks with different technologies on the memory layer. In parallel with hybrid memory architecting, optimizing the number and placement of through silicon vias as a viable solution in building three-dimensional (3D) CMPs is another important target of the proposed approach. Experimental results show that the proposed method outperforms 3D CMP designs with hybrid and traditional memory architectures in terms of both energy delay products (EDPs) and performance parameters. The proposed method improves the EDPs by an average of about 43% compared with SRAM design. In addition, it improves the throughput by about 7% compared with dynamic RAM (DRAM) design.