• Title/Summary/Keyword: under-determined system

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Effects of Inoculation of Bacillus subtilis Cells on the Fermentation of Korean Traditional Soy Paste(Doenjang) (메주 제조 시 Bacillus subtilis의 첨가가 재래식 된장의 발효에 미치는 영향)

  • Rhee, Chang-Ho;Kim, Won-Chan;Rhee, In-Koo;Park, Heui-Dong
    • Food Science and Preservation
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    • v.15 no.4
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    • pp.598-605
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    • 2008
  • Korean traditional soy paste(Doenjang) was fermented for 90 days using, as a starter, a Meju prepared by inoculation of Bacillus subtilis cells. Changes in physiochemical and functional properties were investigated during fermentation. Amylase and protease activities increased and showed maximal levels(4.11 and 7.75 units/mL, respectively) after 60 days of fermentation. Both enzyme activities then fell. Inhibitory activities of the soy paste against tyrosinase and angiotensin converting enzyme(ACE) increased during the fermentation period. Antimutagenic activities during fermentation were determined using the S. enterica serovar Typhimurium TA100 and TA98 analysis system. No significant differences in activity were observed in soy pastes prepared with or without B. subtilis. Antimutagenic activities against the activities of N-methyl-N'-nitro-N-nitrosoguanidine(MNNG) and 4-nitro-O-phenylenediamine (NPD) increased and reached 70.33% and 60.22%, respectively, after 90 days of fermentation, as assessed using the tester strain TA100. Against the actions of NPD and 4-nitroquinoline-1-oxide(NQO), antimutagenic activities also increased during fermentation and reached 50.84% and 47.01%, respectively, as assessed using the tester strain TA98. The genistin content was much higher(187.48 g/g) in soy paste prepared using B. subtilis inoculation than the level(31.30 g/g) seen in soy paste prepared without bacterial inoculation, although the contents of daidzein and genistein were slightly reduced under such circumstances.

Effect of Sugars on Cell Growth and Lipase Production by Trichosporon cutaneum (Trichosporon cutaneum의 균체생육(菌體生育) 및 Lipase 생산(生産)에 미치는 당류(糖類)의 영향)

  • Kim, Seung-Yeol
    • Korean Journal of Agricultural Science
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    • v.4 no.1
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    • pp.105-111
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    • 1977
  • Inhibitory effect of sugars on lipase production by Trichosporon cutaneum was observed in the previous study (Kim, 1972), and inhibition was distinctive by the addition of glucose, fructose, mannose, xylose and arabinose to the soybean meal medium among various carbon sources. These experiments were carried out to study the effect of sugars on cell growth and lipase production by the strain using the soybean extracts liquid medium under a shaking culture system. Changes in color and pH of the medium were caused by heat sterilization when various sugars were added. To elucidate the possible effect of these coloring matters on lipase production and cell growth: changes in pH of the culture, cell concentration and level of the enzyme activities were determined when the culture was grown for 48 hours at $30^{\circ}C$ on a reciprocal shaker. The results obtained were as follows: 1. Density of brownish color which formed during heat sterilization was varied with the variety of sugar used, ie, strong in pentose such as xylose: weak in hexose such as galactose, mannose, glucose: very weak in disaccharide such as maltose, sucrose. When the color density was stronger, decrease in pH after sterilization was marked. 2. Cell growth and lipase production was not so effect by the coloring matters as by sugars. 3. The more the cell mass of the culture, the lower the level of lipase production in the culture supernatant. 4. Among the sugars which caused the distinctive inhibition of lipase production, a slight relief of inhibition was noticed by the addition of xylose, whereas the cell growth was repressed. 5. When cell growth was better, decrease in pH of the medium was greater during cultivation.

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A Study on Egress Algorithm for High-rise Buildings Using Egress Simulation (피난시뮬레이션을 이용한 초고층건물의 피난 알고리즘 연구)

  • Kim, Won Kook;Seo, Dong Hyun
    • Fire Science and Engineering
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    • v.32 no.1
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    • pp.33-39
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    • 2018
  • When the fire in the high-rise building was not extinguished in its early stage and propagated over its origin, safe egress becomes one of the most important factor to minimize the casualties. Recently fire protection for high-rise building has been reinforced after experiencing the series of disastrous fires. But, we still find many high-rise buildings do not comply with those reinforcement. And also there is a possibility of failure of reinforced fire protection system. Under these situation safe egress guide would be the final layer of protection. In this study existing egress methods were identified and evaluated. According the result of study, priority in egress should be given to the tenants on the floor of fire origin and floors exposed to the risk of fire. Then, the rest of the tenants can be evacuated simultaneously. Floors exposed in fire risk shall be determined by fire tests and/or fire simulations. But, the result of fire monitoring shall override preliminary estimations. Egress time for each algorithm was estimated by egress simulation and the result was compared. There was a little difference in egress time between total egress and phased egress, and a big difference between using stairs only and using elevators and stairs together. to a constant thickness between layers constituting a firefighter's protective clothing should be considered in the future.

Determination of Governing Law in International Commercial Arbitration (국제상사중재(國際商事仲裁)에서 준거법(準據法)의 결정(決定))

  • Oh, Won-Suk
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
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    • v.29
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    • pp.39-61
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    • 2006
  • The governing law in international commercial arbitration may be divided into governing arbitration law and governing substantive law. The former governs the parties' arbitration agreement and the conduct of any subsequent arbitration. But the later governs the parties' substantive rights and obligations, which means the law that governs contract formation and performance, and the law to be applied by the arbitrator to the merits of the dispute. The purpose of this paper is to examine how to determine the substantive governing law when there is express choice or implied choice between parties. Moreover this author checked any restrictions on party autonomy and also any possibilities to deviate from the governing law. In case of express choice the sources of the law or rules of law might be the national law of one of the parties, the neutral law, the general principles of law or lex mercatoria according to the arbitration law selected by the arbitral tribunal. Some arbitration laws or rules empower the arbitrator to decide the case ex aequo et bono or to act as amiable compositions. If the governing law could be determined expressly or impliedly by the parties, the arbitral tribunal would make a selection. In this case the criteria for selecting a governing law are not exactly same from country to country. But failing any indication by the parties as to governing law, the arbitral tribunal should apply the rules of law, the law or the law under the rule of conflict that the arbitrators consider applicable, according to the governing arbitration law. Among the connecting factors offered by the conflict rules, (which means the factors that the arbitrators consider applicable), some legal systems give precedence to the formation of the contract, other system to the place of performance of the contract, and others to the closest connection or centre of gravity. But the Rome Convention, which unified the conflict rules of the contracting states, gives precedence to the law of the domicile of the party which has to effect the performance which is characteristic of the contract. Finally this author suggested the Choice of Law Clause which covers governing substantive law and governing arbitration law at the same time. Thus the UNIDROIT Principles as well as any national law may be included as a governing law in international arbitration. So when we make sales or service contract, we should take into consideration of the UNIDROIT Principles as a governing law or a supplement to the governing law.

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A Six-Layer SVAT Model for Energy and Mass Transfer and Its Application to a Spruce(Picea abies [L].Karst) Forest in Central Germany (독일가문비나무(Picea abies [L].Karst)림(林)에서의 Energy와 물질순환(物質循環)에 대(對)한 SLODSVAT(Six-Layer One-Dimensional Soil-Vegetation-Atmosphere-Transfer) 모델과 그 적용(適用))

  • Oltchev, A.;Constantin, J.;Gravenhorst, G.;Ibrom, A.;Joo, Yeong-Teuk;Kim, Young-Chai
    • Journal of Korean Society of Forest Science
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    • v.85 no.2
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    • pp.210-224
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    • 1996
  • The SLODSVAT consists of interrelated submodels that simulate : the transfer of radiation, water vapour, sensible heat, carbon dioxide and momentum in two canopy layers determined by environmental conditions and ecophysiological properties of the vegetation ; uptake and storage of water in the "root-stem-leaf" system of plants ; interception of rainfall by the canopy layers and infiltration and storage of rain water in the four soil layers. A comparison of the results of modeling experiments and field micro-climatic observations in a spruce forest(Picea abies [L].Karst) in the Soiling hills(Germany) shows, that the SLODSVAT can describe and simulate the short-term(diurnal) as well as the long-term(seasonal) variability of water vapour and sensible heat fluxes adequately to natural processes under different environmental conditions. It proves that it is possible to estimate and predict the transpiration and evapotranspiration rates for spruce forest ecosystems on the patch and landscape scales for one vegetation period, if certain meteorological, botanical and hydrological information for the structure of the atmospheric boundary layer, the canopy and the soil are available.

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New Sidelobe Canceller for 3-D Phased Array Radar in Strong Interference (강한 간섭 신호를 제거하기 위한 3차원 위상배열 레이다용 새로운 부엽제거기)

  • Cho, Myeong-Je;Han, Dogn-Seog;Jung, Jin-Won;Kim, Soo-Joong
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.35S no.10
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    • pp.144-155
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    • 1998
  • The array weights that will maximize the SNR for any type of noise environment are determined by the function of the antenna design configuration and the directions of receiving target and interference signals. The conventional SLCs(sidelobe cancellers) using the SNR maximization perform worst from the saturation of the receiving system of main channel when the main antenna has pattern with high gain at the arrival angle of strong interference. In this paper, the new SLC is accomplished by using two independent antenna architecture. Main antenna is implemented with adaptive nulling, which is used for rejecting high-power interference primarily. Auxiliary antenna is realized with adaptive array for receiving interference signal to be suppressed completely, which has a characteristics of sufficient gain for every direction. The new SLC is implemented with above both antennas. We show that the new SLC, which consists of the adaptive nulling main antenna and the adaptive array auxiliary antenna, is useful in reducing the effect of strong interference like jammer, because the adaptive nulling at main antenna prevents its receiver and signal processor for saturation by strong interference. The proposed SLC has improved SNR over the conventional SLCs. The improved SNR at sidelobe region is typically more than 7 dB for a given test signal. Moreover, it improves the SNR of about 20 dB under strong interference at mainlobe.

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The Joint Determination of Leverage and Debt Maturity (레버리지와 부채만기 결정의 상호관계)

  • Kim, Chi-Soo;Kwon, Kyeung-Taek
    • The Korean Journal of Financial Management
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    • v.22 no.1
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    • pp.1-36
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    • 2005
  • In this study, we analyzed determinant factors of leverage ratio and debt maturity for Korean firms in the simultaneous equation system using 2SLS (two stage least square) method under assumption that two variables are jointly determined in the capital structure decision. As a result of the analysis, we found that leverage ratio and debt maturity are positively related. Also, as for determinant factors of debt maturity, agency cost hypothesis, asset maturity matching hypothesis, signalling and liquidity risk hypothesis are all generally supported, and further leverage ratio are significantly positively related with firm size, but negatively related with default risk. However, when we divided samples into groups according to bank debt level and Chaebul affiliation, with contrast to existing study which worked on similar issues with OLS, we found no evidence supporting the argument that the information asymmetry problem is less severe in firms with more bank debt, whereas information asymmetry and financial constraint problems are more severe in non-Chaebul affiliated firms.

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Third-Party Financing Contracts Between Energy Users and Energy Saving Companies (비대칭정보하에서의 최적계약 도출 -에너지절약시장)

  • Kang, Kwang-Kyu
    • Journal of Environmental Policy
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    • v.8 no.4
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    • pp.75-94
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    • 2009
  • The process of obtaining third-party financing contacts was analyzed via a two-stage game model: a "signaling game" for the first stage,and a "principal-agent model" for the second stage. The two-stage game was solved by a process of backward induction. In the second stage game, the optimal effort level of the energy saving company (ESCO), the optimal compensation scheme of the energy user, and the optimal payoffs for both parties were derived for each subgame. The optimal solutions forthe different subgames were then compared with each other. Our main finding was that if there is some restriction on ESCO's revenue (e.g. a progressive sales tax) that causes ESCO's revenue toincrease at a decreasing rate, then the optimal sharing ratio is uniquely determined at a level of strictly less than one under a linear compensation scheme, i.e. a unique balance exists. Subgames have a unique equilibrium arrived at separately for each situation,. Within this equilibrium, energy users accept energy audit proposals from H-type ESCOs with high levels of technology, but reject proposals from L-type ESCOs with low levels of technology. While L-type ESCOs cannot attain profits in the third-party financing market, H-type ESCOS can pocket the price differential between L-type and H-type audit fees. Accordingly, revenues in an H-type ESCO equilibrium increase not only in line with the technology of the ESCO inquestion, but also faster than in an L-type equilibrium due to more advanced technology. At the same time, energy users receive some positive payoff by allowing ESCOs to perform third-party financing tasks within their existing energy system without incurring any extra costs.

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Feasibility of Bladder Compression Molded Prepreg as Small Wind Turbine Blade Material (소형 풍력 터빈 블레이드 재료로서 블래더 가압 방식 몰드 성형 프리프레그의 타당성)

  • Yi, Bo-Gun;Seo, Seong-Won;Song, Myung-Ho
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.33 no.2
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    • pp.95-101
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    • 2020
  • The wind turbine blades should be designed to possess a high stiffness and should be fabricated with a light and high strength material because they serve under extreme combination of lift and drag forces, converting kinetic energy of wind into shaft work. The goal of this study is to understand the basic knowledge required to curtail the process time consumed during the construction of small wind turbine blades using carbon fiber reinforced polymer (CFRP) prepeg composites. The configuration of turbine rotor was determined using the QBlade freeware program. The fluid dynamics module simulated the loads exerted by the wind of a specific speed, and the stress analysis module predicted the distributions of equivalent von Mises stress for representing the blade structures. It was suggested to modify the shape of test specimen from ASTM D638 to decrease the variance in measured tensile strengths. Then, a series of experiments were performed to confirm that the bladder compression molded CFRP prepreg can provide sufficient strength to small wind turbine blades and decrease the cure time simultaneously.

Critical Elastic Buckling Load Investigation of Aluminium Alloy A6082-T6 Square plate Subjected to Patch Loading (패치 로딩을 받는 알루미늄 합금 A6082-T6 사각형 판의 임계 탄성좌굴하중 검토)

  • Oh, Young-Cheol;Ko, Jae-Yong
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.20 no.4
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    • pp.451-460
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    • 2014
  • In this paper, we examined the problem of the structural stability according to the patch load of a rectangular plate that reflects the material properties of A6082-T6 is used primarily for marine plant structure. it applied to the four patch loading shapes, the effect of aspect ratio, a boundary condition and calculated the critical elastic buckling load. Calculating the critical elastic buckling load, During the eigenvalue buckling analysis it is applied to the shell181 as 4 node shell element. when the plate subjected to patch loading compare to the plate under a uniform axial compression load, it is possible observed to occur the different elastic buckling behaviour and it could be confirmed that it is affected significantly on a variable position and type of loadings, such as the effect of the aspect ratio. Also, Critical elastic buckling load according to th patch loading type in simply supported rectangular plate a/b=1.0, ${\gamma}b$=200mm are calculated 67%(Loading type I), 119 %(Loading type II), 76 %(Loading type III), 160 %(Loading type IV), respectively. Loading type I and III could be determined with the strong elastic buckling behavior much more than Loading type II and IV.