• 한국자동차공학회논문집
• /
• 제5권1호
• /
• pp.1-13
• /
• 1997

The key point that guarantees the durability of the ceramic monolith filter is to lower peak temperature and temperature gradient inside filter during regeneration. The control of the exhaust gas flow rate into the filter, by the bypass technique of the exhaust gas, enables the gas temperature in filter to be constant for regeneration. A couple of methods, which are the ON/OFF and PID control of the bypass valve, were used for feedback control of the gas temperature. These techniques showed that the ceramic filter was regenerated perfectly under the peak temperature and peak temperature gradient limitations for durability.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1998년도 하계학술대회 논문집 F
• /
• pp.2057-2059
• /
• 1998

In order to maintain a high quality output voltage, conventional UPS systems use complex filters with large passive components. To overcome this drawback, real time feedback control schemes have been invested. However, these techniques require a high inverter switching frequency to dynamically adapt to changing load conditions reduce harmonics of the output voltage, thereby rendering the system inadequate for high power applications. This paper presents real time digital signal processor(DSP) control of a large capacity UPS system feeding nonlinear loads to provide a sinusoidal inverter output voltage, unity input power factor, low bus voltage ripple, and excellent transient response.

• Elastomers and Composites
• /
• 제57권4호
• /
• pp.215-221
• /
• 2022

In this study, high-penetration asphalt with low greenhouse gas emissions was used in the asphalt mixing process to reduce the carbon emissions during the reaction due to its capacity to be produced even at low temperatures. In effect, cationic, anionic, and non-ionic dispersants were added and mixed in different feeding ratios, seeking an effective dispersion of the modifiers (SIS, PS, TPEE, and SEBS) into the high-penetration asphalt matrix and forming an asphalt binder with a melting point of 120 ℃. The compatibility of the modifiers and the high-penetration asphalt was examined using SEM and DSC techniques, and the role of NDP-1 as a dispersant was carefully investigated with respect to dissolution time. The analyses showed that: (1) the dispersibility of the asphalt binder is good when the non-ionic dispersant is used; (2) as the concentration of the non-ionic dispersant increases, the dissolution time decreases and the domain size contracts; (3) the ND70-PS has the shortest dissolution time, the lowest agglomeration rate, and a single Tg value.

• Animal Bioscience
• /
• 제37권4_spc호
• /
• pp.742-754
• /
• 2024

Asia is not only the primary region for global pig production but also the largest consumer of pork worldwide. Although the pig production in Asia has made great progress in the past, it still is confronted with numerous challenges. These challenges include: inadequate land and feed resources, a substantial number of small-scale pig farms, escalating pressure to ensure environmental conservation, control of devastating infectious diseases, as well as coping with high temperatures and high humidity. To solve these problems, important investments of human and financial capital are required to promote large-scale production systems, exploit alternative feed resources, implement precision feeding, and focus on preventive medicine and vaccines as alternatives to antibiotics, improve pig breeding, and increase manure recycling. Implementation of these techniques and management practices will facilitate development of more environmentally-friendly and economically sustainable pig production systems in Asia, ultimately providing consumers with healthy pork products around the world.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제7권1호
• /
• pp.43-51
• /
• 2002

The cloning and expression of $\beta-glucosidase$ II, encoded by the gene ${\beta}glu2$, from thermotolerant yeast Pichia etchellsii into Escherichia coli is described. Cloning of the 7.3 kb BamHI/SalI yeast insert containing ${\beta}glu2$ in pUC18, which allowed for reverse orientation of the insert, resulted in better enzyme expression. Transformation of this plasmid into E. coli JM109 resulted in accumulation of the enzyme in periplasmic space. At $50^{\circ}C$, the highest hydrolytic activity of 1686 IU/g protein was obtained on sophorose. Batch and fed-batch techniques were employed for enzyme production in a 14 L bioreactor. Exponential feeding rates were determined from mass balance equations and these were employed to control specific growth rate and in turn maximize cell growth and enzyme production. Media optimization coupled with this strategy resulted in increased enzyme units of 1.2 kU/L at a stabilized growth rate of $0.14\;h^{-l}$. Increased enzyme production in bioreactor was accompanied by formation of inclusion bodies.

• 멤브레인
• /
• 제29권1호
• /
• pp.61-65
• /
• 2019

이방성 입자는 독특한 물리적 특성 때문에 다양한 분야에서 발표되고 있다. 여기서, 이방성 도토리구조 나노 입자를 제조하기 위해 새로운 동적 상분리 방법이 도입된다. 동적 상분리 방법은 용제 증발 및 무용제에 의한 침전으로 구성된다. 하부층은 비용매 희석제로서 물을 공급함으로써 제어되며, 상부층의 상분리는 휘발성 용매의 확산 및 증발에 의존한다. 이 상태에서, 도토리 형 입자가 제조되었다. 물이 채워진 밀폐된 상자(자발적 상분리)하에서, 단분산 폴리스틸렌 입자가 합성되었다. 동적 상분리와 자발적 상분리가 공존할 때, 캡과 입자의 크기가 변경되었다. 또한, 폴리스틸렌 용액의 부피는 입자 형상에 영향을 미친다. 독특한 구조가 다양한 응용 분야에 활용될 수 있기 때문에 멤브레인 기반의 제어된 물 공급과 같은 첨단 기술이 개발되면 단분산의 도토리와 같은 입자가 제조될 수 있을 것이다.

• 한국작물학회:학술대회논문집
• /
• 한국작물학회 1998년도 21세기 한반도 농업전망과 대책(한국작물학회.한국육종학회 공동주관 심포지움 회보)
• /
• pp.266-287
• /
• 1998

Environmental conditions and expected profit are the major criteria to select crops to be cultivated in any region. Traditionally, miscellaneous crops have been cultivated as alternative crop in case of unfavorable climate or supplementary crop in marginal lands. Since the successful breeding of high yielding varieties of staple crops and development of cultural techniques in 1970s in Korea, production of miscellaneous crops decreased markedly due to the rapid commercialization of agriculture and increased productions of horticultural crops, although yields have been doubled during the last $2\~3$ decades. On the other hand, animal husbandry has been developing remarkably parallel with national economic development and the increased consumption of animal products. As a result, imports of feed grains such as corn have increased rapidly, while roughage production became lower than demand. Among miscellaneous crops, corn production increased markedly through the development of hybrids and due to its importance as silage crops. Acreage of corn production including grains, fresh corns and feeding is about 120,000 ha, while acreage of buckwheat is about 5,000 ha and those of other miscellaneous crops decreased to a level of about 1,000 ha. Although miscellaneous crops have low yield potential and are unprofitable due to low price and imports of cheap foreign products, they should be kept to cultivate. Miscellaneous crops are important components that maintain diversity among upland crops as well as alternative crops in case of unfavorable climate. The low yield potential of miscellaneous crops might be due to lack of efforts to breed high yielding varieties and to develope cultural techniques. Continuous investment in research, exploitation of new utilization for miscellaneous crops as sustainable crop, honey crop and sightseeing crop, and development of healthy and special foods will promote their cultivation. Animal feeding in Korea depends mainly on formula feeds. As the number of animals increases to meet demand of animal products, there is no alternative way but to import grains to feed them. But roughage production, which is necessary for normal growth of ruminant animals, should be increased. However, lack of arable land and pasture land limits the production of good roughages. It is estimated that number of course for meat and milk production will be $2.5{\~}2.6$ million and total of $6.2{\~}7.5$ million tons of roughages should be produced. This implies that more than 1 million tons of roughage are needed, although pasture land, upland for forage crops, forage crops after rice cultivation and rice straw are utilized. Therefore, new reclamation of pasture land, increased roughage production in cultivating land, increased cultivation of forage crops after rice, more utilization of rice straw and active exploration of indigenous plant species as roughage resources should be promoted

• Fisheries and Aquatic Sciences
• /
• 제19권5호
• /
• pp.23.1-23.7
• /
• 2016

The effects of daily feeding frequency (Exp I), water temperature (Exp II), and stocking density (Exp III) on the growth of river puffer, Takifugu obscurus, juvenile fish of 10 and 40 g in body weight were examined to develop effective techniques to produce river puffer in a non-exchange water system. In Exp I, fish were fed commercial floating feed with 45 % protein one to five times per day to apparent satiation each by hand daily for 8 weeks at $25^{\circ}C$. In both the 10- and 40-g size groups, the final body weight, daily feed consumption, and weight gain of fish fed one meal per day were significantly lower than those of fish fed five meals per day (P < 0.05). However, there were no significant differences in the final body weight, daily feed consumption, and weight gain among fish fed two, three, and five meals per day. Feed efficiency showed decreasing tendency with increasing size of fish. In Exp II, fish of 10 and 40 g in initial body weight were reared with the commercial feed at $15-30^{\circ}C$ for 8 weeks. The weight gain of fish increased with raising water temperature up to $25^{\circ}C$ and decreased drastically at $30^{\circ}C$ for both sizes. The Q10 of specific growth rate was decreased with raising water temperature from 5.04 (temperature interval, $15-20^{\circ}C$) to 0.66 ($25-30^{\circ}C$) for the 10-g fish and from 4.98 to 0.31 for the 40-g fish. In Exp III, the effect of stocking density on growth was examined with fish of 10 and 40 g in initial body weight. The final body weight for initial stocking densities of 4, 8, and $12kg/m^3$ was significantly higher than that of $20kg/m^3$ for the 10-g fish, and the final stocking density reached 10.1, 19.2, 28.7, and $39.9kg/m^3$, respectively. For the 40-g fish, the final body weight for initial stocking densities of 3 and $6kg/m^3$ was significantly higher than that of 9 and $15kg/m^3$ and the final stocking density reached 7.38, 13.5, 17.1, and $27.5kg/m^3$, respectively (P < 0.05). In both groups, weight gain tended to decrease with increasing stocking density; however, survival showed no significant difference.

• 한국멀티미디어학회논문지
• /
• 제23권5호
• /
• pp.641-649
• /
• 2020

As the usage of mobile devices extremely increases, malicious mobile apps(applications) that target mobile users are also increasing. It is challenging to detect these malicious apps using traditional malware detection techniques due to intelligence of today's attack mechanisms. Deep learning (DL) is an alternative technique of traditional signature and rule-based anomaly detection techniques and thus have actively been used in numerous recent studies on malware detection. In order to develop DL-based defense mechanisms against intelligent malicious apps, feeding recent datasets into DL models is important. In this paper, we develop a DL-based model for detecting intelligent malicious apps using KU-CISC 2018-Android, the most up-to-date dataset consisting of benign and malicious Android apps. This dataset has hardly been addressed in other studies so far. We extract OPcode sequences from the Android apps and preprocess the OPcode sequences using an N-gram model. We then feed the preprocessed data into LSTM and apply the concept of Information Gain to improve performance of detecting malicious apps. Furthermore, we evaluate our model with numerous scenarios in order to verify the model's design and performance.

• Journal of Chest Surgery
• /
• 제47권2호
• /
• pp.167-170
• /
• 2014

Herein, we present a case of a successful treatment of persistent type 2 endoleaks associated with aneurysmal sac enlargement after endovascular aneurysm repair in an elderly patient. We confirmed the diagnosis by abdominal computed tomography and selective angiography revealing an 11.0-cm aneurysm sac with type 2 endoleaks. An attempt for the endovascular embolization of collateral arteries was unsuccessful due to anatomic variations and their multiple complex communications. Instead, transperitoneal sacotomy and direct suturing on the feeding target vessels was successfully performed without any endograft damage. In conclusion, sacotomy appears to be a feasible therapeutic substitute where endovascular or other techniques have a high risk of failure and lead to unsuccessful results.