• Journal of Aerospace System Engineering
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• v.18 no.4
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• pp.27-33
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• 2024

This study deals with the demonstration of precision agriculture technology that can predict the health status of crops by analyzing the vegetation index (NDVI) using a drone equipped with a multi-spectral camera and an EO/IR camera. The multi-spectral camera measures crop reflectance to determine the vegetation index, while the EO/IR camera detects temperature changes in crops to evaluate water stress and health status. Data from this study can improve agricultural productivity and optimize the use of chemical fertilizers and pesticides. Moreover, integrating object recognition technology in the future could turn precision agriculture into a vital alternative for enhancing the sustainability of agriculture.

• Korean Journal of Poultry Science
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• v.20 no.3
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• pp.141-149
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• 1993

In order to develop a poultry manure dryer, a pilot dryer was designed and drying experiments were conducted to investigate the drying characteristics of poultry manure. According to the results, the pilot dryer could be operated without any air pollution problems. When poultry manure was dried from 79.2%(w.b. basis) moisture content, the final moisture content ranged from 38.7% to 57.9% depending upon the drying conditions. The drying results showed that drying rate was 189.8~198.0 kg/h and moisture evaporation rate was 124.0~125.4kg-$H_2$O/L. For this drying, electricity requirement was 9.5~19.3 Wh/kg and fuel consumption rate was 6.9~9.3 kg-$H_2$O/L with 50.2~65.1% thermal efficiency.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2002.11a
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• pp.59-63
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• 2002

1997년 홍콩 가금시장에서의 H5N1 조류독감바이러스의 발병은 18명의 감염된 사람 중에서 6명의 사람의 생명을 앗아갔다. 이 사건은 조류독감바이러스가 매개체를 통하지 않고 닭에서 바로 사람에게 감염한 처음 있는 사건이다. 홍콩가금시장에서의 역학조사는 H5Nl과 H9N2 조류독감바이러스가 함께 공존한다는 것을 밝혔다. 가금에서는 H5N1과 H9N2 조류독감바이러스가 검출되었다. 우리는 H5N1 조류독감바이러스로부터 자을 방어하는데 H9N2 조류독감바이러스의 역할에 대해 연구했다. H5N1과 H9N2 바이러스의 혼합바이러스를 동시에 자에 접종하면 자은 생존하지 못했다. 그러나, H5N1 조류 독감바이러스감염 이전에 H9N2 조류독감바이러스를 감염한 닭들은 생존할 수 있었다 H9N2 조류 독감바이러스로 감염된 닭으로부터 얻어진 혈청은 H5N1 조류독감바이러스와 교차반응을 일으키지 않는다. H9N2 조류독감바이러스로 감염시킨 닭으로부터 얻어진 T임파구 또는 CD8 T임파구를 감염하지 않은 닭에 주입할 때 닭은 H5N1 조류독감바이러스로부터 생존할 수 있었다. 실험실외 킬러임파구실험은 H9N2 조류독감바이러스로 감염된 닭으로부터 얻어진 T임파구는 H5N1과 H9N2 조류독감바이러스로 감염된 목표세포를 동시에 감지했다. 게다가, 생체내 T임파구의 제거실험은 교차보호면역은 a/b TCR를 가진 CD8 T임파구가 중요한 역할을 하며, a/b TCR (Vbl)형의 T임파구가 목표세포를 감지한다는 것을 증명했다. H9N2 조류독감바이러스에 의한 방어면역은 시간이 지남에 따라 감소를 했고, 감염 100일까지 방어력을 나타냈다. 1997년 조류독감바이러스인 H5N1의 홍콩에서의 발병에 대한 풀리지 않은 것 중의 하나는 약 20%의 조류들이 매우 치사율이 높은 H5N1 독감바이러스를 가지고 있음에도 홍콩가금시장에서의 대부분의 닭들은 건강했다. 얻을 수 있는 정보에 따르면 대부분의 자들은 H5N1조류독감바이러스를 변으로 방출했고, 단지 두 곳의 가금시장에 있는 자들이 질병증상을 보였다. 홍콩가금시장에서 분리된 모든 H5N1 조류독감바이러스를 닭에 감염하면 100%의 치사율을 나타낸다. 바이러스 측면에서의 연구에 따르면, H9N2 조류독감바이러스는 홍콩가금시장에서 두 번째로 많이 분리되었다. H9N2 조류독감바이러스에 대한 연구에 따르면 세 가지 형이 홍콩가금시장에서 검출되었다. 1997년에 가장 많이 분리된 H9N2 조류독감바이러스는 PB1과 PB2가 A/Chicken/HongKong /156/97 (H5N1)과 유전적으로 유사한 A/HongKong/G9/97 (H9N2)형이다. A/Chicken/Hong Kong/156/97(H5N1)의 나머지 유전자는 A/Chicken/HongKong/739/94 (H9N2)와 A/chicken /Hong Kong/G23/97의 유전자와 비슷하다. 하나의 A/Quail/Hong Kong/G1/97은 Quail에서 분리되었고, 두 개의 A/Duck/Hong Kong/Y280/97 (H9N2)은 오리에서 분리되었다. A/Quail/Hong Kong/G1/97 (H9N2)의 6개의 내부유전자는 A/HongKon9/156/97 (H5N1)에 유사하나, A/Duck/ Hongkong/Y280/97 (H9N2)의 유전자는 A/HongKong/156/97 (H5N1)과 유사하지 않다. 킬러임파구는 바이러스로 감염된 목표세포를 MHC에 의존하여 파괴한다. 독감바이러스 특이 킬러임파구는 독감바이러스로 감염된 mice의 폐로부터 독감바이러스를 제거하는데 중요하다고 알려져 있다. 독감바이러스의 HA단백질은 특이 킬러임파구의 주요 목표항원 단백질이 아니다. 내부단백질인 nucleoprotein, polymerase (PB1 PB2, PA), Matrix protein, 그리고 비 구조단백질인 NS1에 대한 특이 킬러임파구의 반응이 사람과 mice에서 보고되었다. 독감바이러스에 대한 mice의 킬러임파구의 인식영역은 제한되어 있다고 알려져 있다. 많은 mice MHC 1은 독감바이러스 단백질의 킬러임파구의 epitope를 표현하지 못한다. 사람 기억킬러임파구는 다양한 종류의 독감바이러스의 단백질을 인식한다고 알려져 있다. 지금까지, 닭에서의 독감바이러스의 킬러임파구에 대한 연구는 되지 않았다.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.11
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• pp.1087-1094
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• 2008

Diazinon is a phosphorothiate insecticide widely used in the world including Korea. This study investigates the feasibility of photolysis and photocatalysis processes for the degradation of diazinon in water. Both photolysis and photocatalysis reactiosn were effective in degrdading diazinon, however lower TOC removals were achieved. In case of photocatalysis, approximately 40% of nitrogen from diazinon was recovered as NO$_3^-$, and less than 5% of phosphorus as PO$_4{^{3-}}$. However, the sulfur in diazinon molecule was completely recovered to SO$_4{^{2-}}$ from photocatalysis reaction, and the recovery from photolysis was 50%, indicating that P=S bond easily breaks first during photolysis and photocatalysis. The poor recoveries of ionic byproducts and TOC from photolysis and photocatalysis indicate the presence of other organic intermediates during reactions. The formation of organic intermediates were identified during reactions using GC/MS and LC/MS/MS, and the main degradation products were diazoxon, and 2-isopropyl-4-methyl-6-hydroxypyrimidine (IMP), respectively. Finally, the acute 48-hr toxicity test using Daphnia magna were employed to measure the toxicity reduction during photocatalysis of degradation. The results showed that the toxicity increased until 180 min of the photocatalysis reaction (from EC$_{50}$ (%) of 69.6 to 13.2%), however, acute toxicity completely disappeared (>100%) after 360 min. The toxicity results showed that the intermediates from photocatalysis such as diazoxon were more toxic than diazinon itself, however these intermediates can be degraded or mineralized with further reaction.

• Journal of KIISE:Information Networking
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• v.34 no.6
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• pp.466-474
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• 2007

Asymmetric networks that the downlink bandwidth is larger than the uplink bandwidth may cause the degradation of the TCP performance due to the uplink congestion. In order to solve this problem, this paper designs and implements the Dynamic Segment Size Control mechanism which offers a suitable segment size for current networks. The proposed mechanism does not require any changes in customer premises but suppress the number of ACKs using segment reassembly technique to avoid the uplink congestion. The gateway which adapted the Dynamic Segment Size Control mechanism, detects the uplink congestion condition and dynamically measures the bandwidth asymmetric ratio and the packet loss ratio. The gateway reassembles some of segments received from the server into a large segment and transmits it to the client. This reduces the number of corresponding ACKs. In this mechanism, the SACK option is used when occurs the bit error during the transmission. Based on the simulation in the GEO satellite network environment, we analyzed the performance of the Dynamic Segment Size Control mechanism.

• Journal of the Korea Society for Simulation
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• v.25 no.2
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• pp.31-40
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• 2016

Wireless sensor networks have been used in many applications such as marine environment, army installation, etc. The sensor data is very important, because all these applications depend on sensor data. The possibility of communication failures becomes high since the surrounding environment of a wireless sense network has an sensitive effect on its communications. In particular, communication failures in underwater communications occur more frequently because of a narrow bandwidth, slow transmission speed, noises from the surrounding environments and so on. In cases of communication failures, the sensor data can be lost in the sensor data delivery process and these kinds of sensor data losses can make critical huge physical damages on human or environments in applications such as fire surveillance systems. For this reason, although a few of studies for storing and compressing sensor data have been proposed, there are lots of difficulties in actual realization of the studies due to none-existence of the framework using network communications. In this paper, we propose a framework for reducing loss of the sensor data and analyze its performance. The our analyzed results in non-framework application show a decreasing data recovery rate, T/t, as t time passes after a network failure, where T is a time period to fill the storage with sensor data after the network failure. Moreover, all the sensor data generated after a network failure are the errors impossible to recover. But, on the other hand, the analyzed results in framework application show 100% data recovery rate with 2~6% data error rate after data recovery.

• Korean journal of applied entomology
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• v.32 no.3
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• pp.354-371
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• 1993

Behavior of adult females of the smoky brown cockroach was observed for 10-15 days continuously by using computer and the automatic sensoring system. Under the light condition of l2L~ 12D, individual variations were generally higher and the periodicity appeared less in terms of the presence time at the micro-habitats and the locomotory activity. The smoky brown cockroach appeared 20.42, 11.50, 6.31 and 2.66 % in a day in averages respectively at the shelter and the places for other individuals, feeding and drinking. It stayed 20.29 % in a day at the shelter when food, water, and other individuals were not supplied. Visiting rates were higher at the feeding and dnnking places than at. the ot.her micro-habitats. The degree of t.he locomotory activity was relatively lower when food, water, and other individuals were not supplied t.han when they were supplied. The Pnncipal Component Analysis (PCA) on the presence at the micro-habitats showed that. t.he presence pattern for each mdividual appeared differently (Q mode) while the differem time zones were grouped to the photophase and scotophase (R mode). When food, water, and other individuals were supplied the degree of grouping was higher at the shelter than at the places for feeding and drinking. When the act.ivityand the presence time at the different micro-habitats were jointly analyzed by PCA, the achvity of the female smoky brown cockroach appeared in relation with the presence time ( %) at the places for feeding and other individuals.

• Korean Journal of Food Science and Technology
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• v.28 no.6
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• pp.995-1000
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• 1996

The present study was attempted to preprare calcium-fortified soymilk using proteases to improve calcium intolerance of soymilk protein and to evaluate its nutritional properties. The protease from Bacillus polymyxa was chosen as an enzyme source because it produced the least bitter taste and calcium-aggregation of soymilk among various enzymes. The optimum treatment time was 10 minutes at $50^{\circ}C$ for the best result. In vitro protein digestibility of calcium-fortified soymilks was comparable with that of control soymilk. Calcium in the digested soymilks was mostly in the ionic form and the amount of ionic calcium increased in accordance with the amount of fortified calcium in soymilk. This suggests that fortified calcium in the soymilk is bioavailable.

• Journal of the Korean Society of Radiology
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• v.4 no.2
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• pp.21-25
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• 2010

Recently, various semiconductor compounds as radiation detection material have been researched for a diagnostic x-ray detector application. In this paper, we have fabricated the CdS detecton sensor that has good photosensitivity and high x-ray absorption efficiency among other semiconductor compounds, and evaluated the application feasibility by investigating the detection properties about energy range of diagnostic x-ray generator. We have fabricated the line voltage selector(LCV) for a signal acquisition and quantities of CdS sensor, and designed the voltage detection circuit and rectifying circuit. Also, we have used a relative relation algorithm according to x-ray exposure condition, and fabricated the interface board with DAC controller. Performance evaluation was investigated by data processing using ANOVA program from voltage profile characteristics according to resistive change obtained by a tube voltage, tube current, and exposure time that is a exposure condition of x-ray generator. From experimental results, an error rates were reduced according to increasing of a tube voltage and tube current, and a good properties of 6%(at 90 kVp) and 0.4%(at 320 mA) ere showed. and coefficient of determination was 0.98 with relative relation of 1:1. The error rate according to x-ray exposure time showed exponential reduction because of delayed response velocity of CdS material, and the error rate has 2.3% at 320 msec. Finally, the error rate according to x-ray dose is below 10%, and a high relative relation was showed with coefficient of determination of 0.9898.

• The Korean Journal of Applied Statistics
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• v.37 no.4
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• pp.525-539
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• 2024

Massive multiplayer online role playing game (MMORPG) is a common type of game these days. Predicting user churn in MMORPG is a crucial task. The retention rate of users is deeply associated with the lifespan and revenue of the service. If the churn of a specific user can be predicted in advance, targeted promotions can be used to encourage their stay. Therefore, not only the accuracy of churn prediction but also the speed at which signs of churn can be detected is important. In this paper, we propose methods to identify early signs of churn by utilizing the daily predicted user retention probabilities. We train various deep learning and machine learning models using log data and estimate user retention probabilities. By analyzing the change patterns in these probabilities, we provide empirical rules for early identification of users at high risk of churn. Performance evaluations confirm that our methodology is more effective at detecting high risk users than existing methods based on login days. Finally, we suggest novel methods for customized marketing strategies. For this purpose, we provide guidelines of the percentage of accessed users who are at risk of churn.