• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.43 no.3
• /
• pp.504-514
• /
• 1994

Combinational automatic test pattern generators (CATPG) have already been commercialized because their algorithms are well known and practical, while sequential automatic test pattern generators(SATPG) have been regarded as impractical because they are computationally complex. A technique to use CATPG instead of SATPG for test generation of sequential circuits is proposed. Redesign of seauential circuits such as Level Sensitive Scan Design (LSSD) is inevitable to use CATPG. Various partial scan techniques has been proposed to avoid full scan such as LSSD. It ha sbeen reported that SATPG is required to use partial scan techniques. We propose a technique to use CATPG for a new partial scan technique, and propose a new CATPG algorithm for the partially scanned circuits. The partial scan technique can be another choice of design for testability because it is computationally advantageous.

• Proceedings of the Acoustical Society of Korea Conference
• /
• autumn
• /
• pp.3-6
• /
• 2000

CELP 계열 보코더중 인터넷 폰 및 화상회의를 목적으로 개발된 G.723.1 보코더에서는 LPC를 LSP로 변환하기 위해 LPC 계수를 이용한 다항식을 구성한 다음 근을 검색하는 방법을 사용하고 있다. 근 검색시에는 256/pi의 범위 안에서 동일한 간격을 갖는 코사인 테이블을 구성하여 순차적으로 검색하게 된다. LSF의 근들은 포만트가 존재하는 대역에서 근들이 나타나게 되므로 유성음의 경우 저주파수 대역에서 무성음의 경우 고주파수 대역에서 많이 분포하게 된다. 하지만 G.723.1에서 사용하는 코사인 테이블은 음성신호의 특성을 고려하지 않고 균등한 간격을 갖는 값들을 사용함으로 음질을 저해할 수 있는 요소를 갖고 있다. 따라서 본 논문에서는 음성의 특성을 고려한 코사인 테이블을 재구성함으로써 음질을 향상시킬 수 있었으며 주관적 음질평가인 MOS 시험결과 평균 1.8 정도의 음질향상을 가져올 수 있었다

• Information and Communications Magazine
• /
• v.34 no.1
• /
• pp.34-39
• /
• 2016

소프트웨어에 이어 하드웨어에서도 오픈소스시대가 열리고 있다, 소프트웨어와 하드웨어 분야에서의 오픈소스의 폭넓은 확산은 ICT 분야의 R&D 활동에서 새로운 연구 방법과 연구 분야의 확장을 가능케 할 것으로 생각된다. 오픈소스 생태계 하에서는 개별 연구조직의 크기나 연구 규모에 따른 장점은 줄어드는 반면 개인의 창의력이나 협업 능력이 연구경쟁력의 원천이 된다. 이에 따라 과거에는 시도하지 않았던 창의적인 선행연구나 시스템적인 융합연구도 가능해질 것이다. R&D는 단지 구현결과물을 얻는 것에 한정되는 것이 아니라, 개념 도출, 이에 따른 설계, 소프트웨어 및 하드웨어 구현, 적합성 및 상호운용성시험, 대규모 실증사업까지의 단계적이고 체계적인 추진과 이에 대한 문서화, 규격화 및 표준화 작업들을 포함한다. 이러한 작업은 순차적이 아니라 동시적으로 수행될 때 상호연계 검증에 따른 완성도 제고와 전주기 활동에 있어 총 시간 단축을 꾀할 수 있다. 본 고에서는 오픈소스 생태계에서 연구자들이 이러한 활동의 효과적인 수행과 협력적 융합연구를 위한 저비용 오픈소스 R&D 동시개발 플랫폼 방안을 제시한다.

• Proceedings of the Korea Contents Association Conference
• /
• 2019.05a
• /
• pp.111-112
• /
• 2019

최근의 전장 환경은 전투 공간에서 파악 가능한 모든 요소를 효과적으로 연계하여 정보의 우월성을 기반으로 전투력을 향상시키는 네트워크 중심전 체제로 진화하고 있다. 이에 우리 군은 네트워크 중심 전장 환경의 핵심 요소로서 전술다대역다기능무전기를 개발해왔으며, 기존 아날로그 방식 무전기를 기반으로 네트워크를 구성하여 운용하는 체계에 순차적으로 적용될 예정이다. 이는 지상 무기체계도 예외는 아니다. 이러한 상황에 따라, 본 논문에서는 지상 무기체계 환경에서 전술다대역다기능무전기의 성능 평가 및 분석을 수행한다. 성능 평가에서는 실제 전술다대역다기능무전기를 기반으로 지휘통제체계와 무장통제장치 간의 무선 통신환경을 모의 구성하여 성능 시험을 수행하였으며, 결과 분석을 통해 전술다대역다기능무전기의 지상 무기체계 적용 가능성을 확인한다.

• Journal of Advanced Marine Engineering and Technology
• /
• v.35 no.8
• /
• pp.1132-1140
• /
• 2011

When the offshore wind power plant is planned to construct, it is important for the wind farm site to figure out the distribution of the weak soil layers that might cause subsidence by the impact of the external moment from the wind plant's load and an oscillating wind load. Coring test is the optimistic method to figure out weak soil layers, but this method have some problem such as condition of the in-situ or economical limitation. In order to make up for the weak points in coring test, the researches using the geostatistics methods is actually done. In this study, setting a fixed coastal area that offshore wind plants construct firstly and Estimation of distribution on the thickness of the weak soil layer through the geostatistic method is conducted. The weak soil layer is sorted by result of the Standard penetration test, geostatistic method is used to ordinary kring and sequential gaussian simulation and compared to both method's result. As a results of study, we found that both methods show similar estimations of deep weak soil layer and we could evaluate quantitatively the uncertainty of the result.

• Journal of IKEEE
• /
• v.16 no.2
• /
• pp.109-115
• /
• 2012

We propose a control system consisted of TRIAC PWM module and sequential start control system attenuating voltage-dip and inrush current caused by starting of inductive load network. To minimize the high voltage-dip and inrush current induced from a large capacity inductive load, we developed a TRIAC PWM module. And we also developed a sequential start control system preventing simultaneous starting of the inductive loads within a same power network. According to the experimental results with the proposed control system, the voltage-dip and inrush current could be effectively attenuated such that they can meet the related international standards and resolve the issues associated with simultaneous starting of multiple inductive loads. By employing this system, power cost usually implemented by the estimation of peak power consumption can be reduced and the power quality of a power distribution system connected to the inductive load network can be stabilized efficiently.

• Journal of Sericultural and Entomological Science
• /
• v.46 no.1
• /
• pp.38-43
• /
• 2004

The strings of Gayageum and Geomungo are usually made of raw silk. It needs good vibration as well as good durability to endure during play the Gayagum and Geomungo. This study was carried out to discuss some effects of twisting number of first and final twisting on the mechanical properties of silk Gayageum strings. Tenacity of strings were largely decreased proportionally with the increase of number of twisting of strings but elongation of strings were in the opposition direction. However, it was needed to hard twisting string for the good vibration. The proper S direction twisting velocity of moving twister during final twisting (Z direction) until three thread become one thread, was 40% of basic twister.

• Korean Journal of Food Science and Technology
• /
• v.28 no.1
• /
• pp.109-116
• /
• 1996

The relationship between antioxidant activities and physicochemical properties of several fractions obtained from freeze-dried (FD) coffee were investigated. The nine kinds of fraction were consecutively extracted from FD coffee with solvents in increasing order of polarity, and the higher polarity of the solvent the higher extraction yield of the fraction. The antioxidant activities of the fractions were determined by Rancimat and oven test on edible oils. The antioxidant activities of the fractions increased in the order of acetone>ethanol>methanol>50% methanol/water>water fraction, and the antioxidant activities of them were higher on lard than on soybean oil. The antioxidant activity of each fraction was strongly related to the contents of total phenol, total nitrogen content and acidity, whereas color intensity, reducing power, carboxylic acid content showed little contribution to the activity. All fractions had three peaks maxima at 208, 275 and 324 nm on UV-visible spectra, but the only one at 324 nm was linealy proportional to the antioxidant activities of the fractions.

• Journal of Korea Society of Industrial Information Systems
• /
• v.19 no.3
• /
• pp.1-7
• /
• 2014

This paper describes the implementation of high speed comparator for the ATE (automatic test equipment) system. The comparator block is composed of continuous comparator, differential difference amplifier(DDA) and output stage. For the wide input dynamic range of 0V to 5V, and for the high speed operation (1~800MHz), high speed rail-to-rail amplifier is used in the first stage. And hysteresis circuits, pre-amp and latch are followed for high speed operation. To measure the difference of output signals between the two devices under test (DUTs), a DDA is applied because it can detect the differences of both common signals and differential signals. This comparator chip was implemented with $0.18{\mu}m$ BCDMOS process and can compare the signal difference of 5mV up to the frequency range of 800 MHz. The chip area of the comparator is $620{\mu}m{\times}830{\mu}m$.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.15 no.3
• /
• pp.345-356
• /
• 2013

Numerical simulation on rock cutting by a TBM disc cutter was carried out using SPH (Smoothed Particle Hydrodynamics) code. AUTODYN3D, a commercial software program based on finite element method, was used in this study. The three-dimensional geometry of a disc cutter and a rock specimen were modeled by Lagrange and SPH code respectively. The numerical simulation was carried out for Hwangdeung granite for 10 different cutting conditions. The results of the numerical simulation, i.e. the relation between cutter force and failure behavior, had a good agreement with those from LCM test. The cutter forces measured in the numerical simulation had 10% deviation from the LCM test results. Moreover, the optimum cutter spacing was almost identical with the experimental results. These results indicate that SPH code can be successfully used had applicability for simulation on rock cutting by a TBM disc cutter. However, further study on Lagrange-SPH coupled modelling would be necessary to reduce the computation time.