• Journal of IKEEE
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• v.9 no.2 s.17
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• pp.123-135
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• 2005

3GPP RLC protocol specification adopted a window-controlled selective-repeat ARQ scheme for provisioning reliable data transmission. Inevitably, the re-ordering issue arises in the 3GPP's ARQ since it belongs to the selective-repeat ARQ clan. A long re-ordering time results in the degradation of throughput and delay performance, and may invoke the overflow of the re-ordering buffer. Also, the re-ordering time must be regulated to meet the requirements of some services which are both loss-sensitive and delay-sensitive. In the 3GPP's ARQ, we may deflate the occupancy of the re-ordering buffer by reducing the window size and/or length of the status report period. Such a decrease, however, deteriorates the throughput and delay performance and encroaches the resource of the reverse channel. Aiming at reducing the occupancy at the re-ordering buffer while suppressing the degradation of throughput and delay performance, we propose threshold-dependent occupancy control schemes, identified as post-threshold and pre-threshold schemes, as supplements to the 3GPP's ARQ. For judging the effectiveness of the proposed schemes, we investigate peak occupancy, maximum throughput and average delay in the practical environment involving fading channels. From the simulation results, we observe that the proposed schemes invoke the performance trade-off between occupancy and throughput in general. Also, we reveal that the post-threshold scheme is able to improve the throughput and delay performance of the ordinary 3GPP's ARQ without inflating the occupancy of the re-ordering buffer.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1840-1842
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• 2002

고전압 대 전류를 필요로 하는 펄스 파워 시스템에서 스위치는 중요한 소자중의 하나이다. 펄스 트랜스포머를 이용하여 고전압 펄스를 만드는 회로에서 대전류 스위칭에는 대부분 스파크 갭 스위치나 싸이라트론을 사용하는데 높은 펄스 반복 율과 긴 수명을 제공하기 위해서는 반도체 스위치를 사용해야한다. 고전압 대전류 펄스파워 시스템에 적합한 반도체 스위치의 스위칭 특성과 제어방식에 관한 연구를 수행하였다 실험에 사용한 스위치는 20 kV, 12.6 kA, 12 ${\mu}s$의 펄스 스위칭이 가능한 ABB사의 반도체스위치 스택 (5SPR-26L4508-8-WC)이다. 실험회로는 콘덴서에 충전을 완료한 다음 스위치와 인덕터를 통하여 방전하도록 구성하였다. 8개의 직렬 연결된 스위치는 광케이블을 사용하여 병렬구동하고, 고주파 스위칭 전류전원을 사용하여 고전압 절연을 하면서 게이트 구동전력을 전달하도록 하였다. 본 논문에서는 스위치 전압과 방전전류를 관측하여 반도체 스위치의 특성을 조사하였다.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.3
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• pp.37-41
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• 2016

In this paper, we introduced a near infrared fluorescence imaging system that has long working distance and analyzed on the effects of measurement variables such as gain, exposure time, working distance, magnification. Fluorescence signal intensity is growing up according to exposure time and magnification increasing, and it is getting stronger according to increase of gain, but the background signal intensity is getting stronger together. It causes low SBR. Due to a laser irradiation method, laser intensity distribution of the introduced system is not uniform and it makes fluorescence signal weak. So, we proposed a solution.

• Journal of fish pathology
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• v.26 no.1
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• pp.39-44
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• 2013

Saprolegnia isolate from wild brook lamprey was identified on the basis of its morphological and molecular characteristics. The isolates showed aseptic hyphae and clavate zoosporagium. Zoospores discharge was typically saprolegnoid. Neither oogomia nor antheridia was observed in this study. ITS sequence obtained from the isolate was compared with other Saprolegnia spp. to analyse their phylogenetic relationships. Results showed that the isolate belongs to clade I including Saprolegnia parasitica. Based on the asexual organs, zoospore discharge manner and ITS sequence analysis, the isolate was identified as S. parasitica.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.35T no.1
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• pp.7-13
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• 1998

The VLSI devices of submicron level trend to have a lowering of reliability because of hot carriers by two dimensional influences which are caused by short channel effects and which are not generated in a long channel devices. In order to minimize the two dimensional influences, much research has been made into various types of source/drain structures. MOS typed tunnel transistor with Schottky barrier junctions at source/drain, which has the advantages in fabrication process, downsizing and response speed, has been proposed. The experimental device was fabricated with p type silicon, and manifested the transistor action, showing the unsaturated output characteristics and the high transconductance comparing with that in field effect mode. The results of trial indicate for better performance as follows; high doped channel layer to lower the driving voltage, high resistivity substrate to reduce the leakage current from the substrate to drain.

• Journal of Practical Agriculture & Fisheries Research
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• v.22 no.2
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• pp.81-88
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• 2020

Pleurotus pulmonarius 8 cultivas, domestically bred, were cultivated and evaluated for cultural properties. The morphological properties of 8 cultivars were big diameter of pileus and short stipe. Stipe was eccentrically combined with pileus. The longest length of stipe was Yeoleumneutali 2ho(72.8mm) while shortest cultivar was Yeoleumneutali 1ho(33.8mm). The diameter of pileus ranged 45.8-62,3mm, Yaksan was the smallest one and Yeoleumneutali 2ho was largest cultivar. Yield was largest in Yeoleumneutali 2ho(80.7g) whereas smallest was in Yeoleumneutali 1ho(35.5g). The highest L value was in Yeoleumneutali 2ho and Hosan. Lightness was not even around pileus but thicker in rim area and thinner in center of pileus. Average period of pinheading and harvest were 4.6 and 8.0 days thus only 3-4 days after pinheadng were required for harvest.

• Annual Conference on Human and Language Technology
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• 1999.10e
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• pp.447-454
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• 1999

본 연구에서는 국어의 본용언과 보조용언이 어떠한 방식으로 처리되는지에 대해 알아보는 것이 목적이다. 영어와 달리 국어는 보조용언이 조동사의 역할을 담당하여 화자의 심리적인 상태나 상(想)을 나타내는 기능을 한다. 따라서 같은 어휘가 본용언으로 쓰일 때와 보조용언으로 쓰일 때 그 의미적 차이는 뚜렷하다. 특히 보조용언으로 쓰일 때는 어휘적 의미가 대부분 사라지고 추상적 의미만 남기 때문에 본용언과의 관련성을 따져보는 것도 중요한 연구과제이다. 또한 우리의 심성어휘집(mental lexicon)에서 본용언과 보조용언이 동일한 영역에서 처리되는지도 알아볼 필요가 있다. 만일 동일한 심성어휘집을 사용한다면 보조용언으로 쓰인 환경에서도 본용언의 어휘적 의미가 활성화될 것이다. 이에 대해 본 연구에서는 정상인 피험자와 실어증환자를 대상으로 실험을 하였다. 정상인 피험자를 대상으로는 SOA가 짧은 조건과 긴 조건에서 각각 보조용언을 어떻게 처리하는 지 살펴보았고, 실어증환자를 대상으로는 정상인 피험자와 비교해서 어떤 양상으로 보조용언을 처리하는 지 살펴보았다. 그 결과 정상인 피험자는 SOA가 짧은 조건에서는 본용언과 보조용언을 모두 동일한 방식으로 의미처리하였다. 즉 보조용언의 어휘적 의미가 본용언과 마찬가지로 SOA가 짧을 때는 활성화되었다. 그러나 SOA가 길어지면 보조용언은 문맥 정보로 인해 어휘적 의미가 억제되어 본용언과 다른 의미로 해석된다는 결론을 얻었다. 이런 정상인 피험자와 비교해 보았을 때, 실어증 환자는 두 가지 양상이 나타났다. 명칭성 실어증환자의 경우, 정상인과 비슷한 결과가 나왔으나 보조용언으로 쓰일 때, 본용언보다 어휘적 의미가 다소 불안정하게 활성화됨을 보였다. 그러나 이해성 실어증환자의 경우, 보조용언으로 쓰일 때 어휘적 의미가 전혀 활성화되지 않아 정상인과는 다른 언어처리를 하고 있음이 밝혀졌다.류의 의미가 모두 활성화되는 것을 보여 주었다. 즉, "먹은"과 간은 어절 이해는 구성 형태소로의 분석과 구성 형태소 어휘 접근을 통해 어절 이해가 이루어진다는 가설을 지지하고 있다. 실험 2에서는 실험 1과 다르게 한 뜻으로만 안일 수밖에 없는 "쥐어"와 같은 어절을 사용하여 이런 경우에도(즉, 어절의 문맥이 특정 뜻으로 한정하는 경우) 구성 형태소로의 분석 과정이 일어나는지를 조사하였다. 실험 2의 결과는 실험 1의 결과와는 다르게 어간의 한가지 의미와 관련된 조건만 촉진적 점화 효과가 나타나는 것을 보여주었다. 특히, 실험 2에서 SOA가 1000msec일 경우, 두 의미의 활성화가 나타나는 것을 보여주었는데, 이 같은 결과는 어절 문맥이 특정한 의미로 한정시킬 경우는 심성어휘집에 활용형태로 들어있다는 것이다. 또한 명칭성 실어증 환자의 경우에는 즉시적 점화과제에서는 일반인과 같은 형태소 처리과정을 보였으나, 그이후의 처리과정이 일반인과 다른 형태를 보였다. 실험 1과 실험 2의 결과는 한국어 어절 분석이 구문분석 또는 활용형태를 통해 어휘 접근되는 가설을 지지하고 있다. 또 명칭성 실어증 환자의 경우에는 지연된 점화과제에서 형태소 처리가 일반인과 다르다는 것이 밝혀졌다. 이 결과가 옳다면 한국의 심성 어휘집은 어절 문맥에 따라서 어간이나 어근 또는 활용형 그 자체로 이루어져 있을 것이다.으며, 레드 클로버 + 혼파 초지가 건물수량과 사료가치를 높이는데 효과적이었다.\ell}$ 이었으며 , yeast extract 첨가(添加)하여 배양시(培養時)는 yeast extract 농도(濃度)가 증가(增加)함에 따라 단백질(蛋白質) 함량(含量)도 증가(增加)하였다. 7. CHS-13 균주(菌株)의 RNA 함량(含量)은 $4.92{\times}10^{-2 }\;mg/m{\ell}$이었으며 yeast ext

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.1D
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• pp.65-72
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• 2011

When an expressway intersects another expressway, a unique connector needs to be designed between the two consecutive exit ramps. In such a case, it is important to design a connector such that there is enough distance for drivers to find their way safely. A current design manual in Korea prescribes the minimum length of the connector as 240 m. In this research, we have suggested a method for calculating the minimum length of a connector in order to check the feasibility of the currently prescribed length. For this purpose, we have attempted to determine the total perception-reaction time and lane-changing time required by a driver. For determining the driver's perception-reaction time, we have used the driver's decision time in addition to the conventional 2.5 s of perception-reaction time for stopping sight distances. We have considered both the design speed and the average travel speed for the calculation of the length. To evaluate the accuracy of the new method, we have chosen four sites on expressways for which relatively high accident rates were recorded. As a result, we could verify that the current limit (240 m) was sufficient for drivers to be able to change lanes in the given specific geometry. However, the prescribed limit should be revised in case the drivers' decision time is considered to be their perception-reaction time. All new approaches for calculating the ideal length of a connector have been carried out by taking into account the design speed as well as the average travel speed. Owing to the characteristics of the specific geometry for two consecutive exit ramps and the large difference between the design speed and the average travel speed in the objective areas, it is more realistic to use the proposed method by keeping the decision time equal to a driver's perception-reaction time, in order to determine the ideal distance that should be maintained between two consecutive exit ramps.

• Journal of Wetlands Research
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• v.20 no.4
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• pp.314-321
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• 2018

In order to quantify nonpoint source pollution, it was proposed to sample at regular intervals of 1 hour for the first 24 hours of storm runoff process by National Institute of Environmental Research for the mixed landuse watershed. However, high frequency sampling requires intensive laboratory analysis and labor costs. In order to investigate the effect of longer sampling interval on the load estimation compared to the 1 hour sampling method, analysis was conducted using monitoring data from rural subwatershed, urban subwatershed, and outlet of the Pungyeongjeongcheon watershed. Statistical analysis revealed that mean of load estimation was not significantly different up to 4 hour sampling frequency. However, 3 hour sampling interval was found to be appropriate for the BOD and TP when it is judged that 10% or less of the difference in loading amount between the 1 hour and other sampling interval is reasonable. The results of this study can be used to conduct an effective monitoring system.

• Korean Journal of Environmental Biology
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• v.35 no.2
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• pp.207-214
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• 2017

There is little information about the seed longevity of wild plants, although seed bank storage is an important tool for biodiversity conservation. This study was conducted to predict the seed viability equation of Agastache rugosa. The A. rugosa seeds were stored at moisture contents ranging from 2.7 to 12.5%, and temperatures between 10 and $50^{\circ}C$. Viability data were fitted to the seed viability equation in a one step and two step approach. The A. rugosa seeds showed orthodox seed storage behaviour. The viability constants were $K_E=6.9297$, $C_W=4.2551$ $C_H=0.0329$, and $C_Q=0.00048$. The P85 of A. rugosa seeds was predicted to 152 years under standard seed bank conditions. The P85 predicted by seed viability equation can be used as basic information for optimization of seed storage processes.