• 제목/요약/키워드: two-time-scale system

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전자상거래가 경제에 미치는 효과 - 물류 정보화를 중심으로 - (The effect of electronic commerce on the economy - logistics industry perspective -)

  • 김범환
    • 기술경영경제학회:학술대회논문집
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    • 기술경영경제학회 1999년도 제16회 동계학술발표회 논문집
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    • pp.281-295
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    • 1999
  • This paper analyses the effects of the increase of logistics outsourcing on the economy which are largely classified into three parts. The firm level and industry level are two among them which will be summarized below. The another is consumers level. On the fm level, the logistics outsourcing of a manufacturing firm not only helps to increase the efficiency of itself and but also confront the competitive environments by weakening the entry barriers, i.e., the emergence of contestable market. The reasons why the efficiency of the firm enhances are also largely divided into two parts. One is due to the reduction of inventory cost by replacing it by the information cost resulting from internet use. The other is owing to reducing the life cycle of production process by the emergence of virtual enterprises which are located in one point in De process of supply chain management. The weakening of entry barriers is directly affected by the drastic increase of internet users in twofold reasons: one is based on the restricted competitive characteristics due to the long-term transaction relationship between logistics providers and the companies who offer logistics services and the other, due to the weakening of the restriction of space and time. The effect of industry level is due to the transition of traditional to virtual vertical integration system The firms corresponding to a connection point in the process of supply chain management would try to realize both the scale of economy and the scope of economy for strengthening the competitiveness. We indicated above the emergence of contestable market however, it is a short-term phenomenon and result in the oligopoly market due to the entry barriers in the long-run sense.

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Identification of New Source of Resistance to Powdery Mildew of Indian Mustard and Studying Its Inheritance

  • Nanjundan, Joghee;Manjunatha, Channappa;Radhamani, Jalli;Thakur, Ajay Kumar;Yadav, Rashmi;Kumar, Arun;Meena, Mohan Lal;Tyagi, Rishi Kumar;Yadava, Devender Kumar;Singh, Dhiraj
    • The Plant Pathology Journal
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    • 제36권2호
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    • pp.111-120
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    • 2020
  • Powdery mildew of Indian mustard (Brassica juncea), caused by Erysiphe cruciferarum, is emerging as major problem in India. All the Indian mustard cultivars presently grown in India are highly susceptible to powdery mildew and so far no resistance source has been reported. In this study, with an aim to identify resistant source, 1,020 Indian mustard accessions were evaluated against E. cruciferarum PMN isolate, at Wellington, The Nilgiris, Tamil Nadu, India under natural hot spot conditions. The study identified one accession (RDV 29) with complete resistance against E. cruciferarum PMN isolate for the first time, which was consistent in five independent evaluations. Genetic analysis of F1, F2 and backcross populations obtained from the cross RSEJ 775 (highly susceptible) × RDV 29 (highly resistant) for two season revealed that the resistance is governed by two genes with semi-dominant and gene dosage effect. Further, a new disease rating system using six scales (0, 1, 2, 3, 4, and 5) has also been proposed in this study to score powdery mildew based on progress of fungal growth in different plant parts of the F2 population. The outcome of this study viz. newly identified powdery mildew-resistant Indian mustard accession (RDV 29), information on inheritance of resistance and the newly developed disease rating scale will provide the base for development of powdery mildew-resistant cultivars of Indian mustard.

Time dependent finite element analysis of steel-concrete composite beams considering partial interaction

  • Dias, Maiga M.;Tamayo, Jorge L.P.;Morsch, Inacio B.;Awruch, Armando M.
    • Computers and Concrete
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    • 제15권4호
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    • pp.687-707
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    • 2015
  • A finite element computer code for short-term analysis of steel-concrete composite structures is extended to study long-term effects under service loads, in the present work. Long-term effects are important in engineering design because they influence stress and strain distribution of the structural system and therefore contribute to the increment of deflections in these structures. For creep analysis, a rheological model based on a Kelvin chain, with elements placed in series, was employed. The parameters of the Kelvin chain were obtained using Dirichlet series. Creep and shrinkage models, proposed by the CEB FIP 90, were used. The shear-lag phenomenon that takes place at the concrete slab is usually neglected or not properly taken into account in the formulation of beam-column finite elements. Therefore, in this work, a three-dimensional numerical model based on the assemblage of shell finite elements for representing the steel beam and the concrete slab is used. Stud shear connectors are represented for special beam-column elements to simulate the partial interaction at the slab-beam interface. The two-dimensional representation of the concrete slab permits to capture the non-uniform shear stress distribution in the horizontal plane of the slab due to shear-lag phenomenon. The model is validated with experimental results of two full-scale continuous composite beams previously studied by other authors. Results are given in terms of displacements, bending moments and cracking patterns in order to shown the influence of long-term effects in the structural response and also the potentiality of the present numerical code.

Rotator cuff repair with or without proximal end detachment for long head of the biceps tendon tenodesis

  • Mardani-Kivi, Mohsen;Asadi, Kamran;Izadi, Amin;Leili, Ehsan Kazemnejad
    • Clinics in Shoulder and Elbow
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    • 제25권2호
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    • pp.101-105
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    • 2022
  • Background: Rotator cuff tears cause pathologies of the long head of the biceps tendon (LHBT). One of the surgical treatments for such a tear is LHBT tenodesis to the humerus. This study aims to compare simultaneous rotator cuff repair and LHBT tenodesis with or without detachment of the proximal end of the LHBT (PELHBT) from its site of adhesion to the glenoid. Methods: This retrospective study involved patients affected by LHBT pathology with rotator cuff tear. The patients were divided into two groups, with or without PELHBT detachment from the glenoid. Therapeutic outcomes were investigated by evaluation of patient satisfaction, pain based on visual analog scale, shoulder function based on Constant score and simple shoulder test, and biceps muscle strength based on the manual muscle testing grading system before surgery, at 6 months, and at the final visit after surgery. Results: Groups 1 and 2 comprised 23 and 26 patients, respectively, who showed no significant differences in demographic characteristics (p>0.05). Shoulder function, biceps muscle strength, pain, and satisfaction rate improved over time (p<0.05) but were not significantly different between the two groups (p>0.05). No post-surgical complication was found in either group. Conclusions: There was no difference in final outcomes of tenodesis with or without detachment of the PELHBT from the supraglenoid tubercle. Such tendon detachment is not necessary.

Tryptophan-Based Hyperproduction of Bioindigo by Combinatorial Overexpression of Two Different Tryptophan Transporters

  • Hyun Jin Kim;Sion Ham;Nara-Shin;Jeong Hyeon Hwang;Suk Jin Oh;Tae-Rim Choi;Jeong Chan Joo;Shashi Kant Bhatia;Yung-Hun Yang
    • Journal of Microbiology and Biotechnology
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    • 제34권4호
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    • pp.969-977
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    • 2024
  • Indigo is a valuable, natural blue dye that has been used for centuries in the textile industry. The large-scale commercial production of indigo relies on its extraction from plants and chemical synthesis. Studies are being conducted to develop methods for environment-friendly and sustainable production of indigo using genetically engineered microbes. Here, to enhance the yield of bioindigo from an E. coli whole-cell system containing tryptophanase (TnaA) and flavin-containing monooxygenase (FMO), we evaluated tryptophan transporters to improve the transport of aromatic compounds, such as indole and tryptophan, which are not easily soluble and passable through cell walls. Among the three transporters, Mtr, AroP, and TnaB, AroP enhanced indigo production the most. The combination of each transporter with AroP was also evaluated, and the combination of AroP and TnaB showed the best performance compared to the single transporters and two transporters. Bioindigo production was then optimized by examining the culture medium, temperature, isopropyl β-D-1-thiogalactopyranoside concentration, shaking speed (rpm), and pH. The novel strain containing aroP and tnaB plasmid with tnaA and FMO produced 8.77 mM (2.3 g/l) of bioindigo after 66 h of culture. The produced bioindigo was further recovered using a simple method and used as a watercolor dye, showing good mixing with other colors and color retention for a relatively long time. This study presents an effective strategy for enhancing indigo production using a combination of transporters.

경종-축산 순환 유기농업의 가치 증진을 위한 농가 간 협동조직화 모델 연구 - 경종-축산 순환 양돈 농가를 사례로 - (A Study on the Cooperative Organization Model among Family Farms for the Value Enhancement of Crop-Livestock Cycling Organic Agriculture - Case of Crop-Livestock Cycling Organic Pig Farm -)

  • 최덕천
    • 한국유기농업학회지
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    • 제28권3호
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    • pp.367-386
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    • 2020
  • The significance of this study was to analyze the quality value of organic livestock pork for the first time based on the results of managing and testing the cycling organic farming of black pork and vegetables within farm for two years. The results of analysis could be summarized as follows. First, the pork of experimental group with crop-livestock cycling farming showed the excellent quality and high consumer preference compared to the control group of general pork or pork from non-crop-livestock cycling organic farming. In the content ratio of Omega-3 as a representative essential fatty acid, it was 1.46 that was about 2.8 times more than general pork (0.52). In case of Omega-6, it had about 2.5 times more than general pork. Especially, the U/S ratio value which was the content ratio of Unsaturated Fatty Acid (UFA, U) of Saturated Fatty Acid (SFA, S), was largely shown in pork (2.93) from cycling organic farming. Second, it would be necessary to maintain the economies of scope shown in crop-livestock cycling organic farming, and the high quality value of livestock products. For this, there should be a value chain model that could realize the economies of scope and economies of scale at the same time based on scaling and diversification through cooperative organization between farmers. Through this, it would be possible to establish a cycling model called 'community cooperative agriculture' by forming local internal markets through cooperation of production-processing and integration of distribution-sale-consumption. For the managerial activation of this cooperative organization, the government should promote/support the small crop-livestock cycling organic farming cooperative organization in local unit. For securing the reliability of crop-livestock cycling organic agricultural products and crop-livestock cycling organic livestock products, it would be necessary to review the introduction of Participatory Guarantee System (PGS).

입자영상유속계를 이용한 자항상태 모형선의 프로펠러 후류 계측 (Propeller Wake Measurement of a Model Ship in Self Propulsion Condition using Towed Underwater PIV)

  • 서정화;유극상;임태구;설동명;한범우;이신형
    • 대한조선학회논문집
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    • 제51권2호
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    • pp.171-177
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    • 2014
  • A two-dimensional particle image velocimetry (2D PIV) system in a towing tank is employed to measure a wake field of a very large crude oil carrier model with rotating propeller in self propulsion condition, to identify characteristics of wake of a propeller working behind a ship. Phase-averaged and time-averaged flow fields are measured for a horizontal plane. Scale ratio of the model ship is 1/100 and Froude number is 0.142. By phase-averaging technique, trajectories of tip vortex and hub vortex are identified and characteristic secondary vortex distribution is observed in the hub vortex region. Propeller wake on the starboard side is more accelerated than that on the port side, due to the difference of inflow of propeller blades. The hub vortex trajectory tends to face the port side. With the fluctuation part of the phase-averaged velocity field, turbulent kinetic energy (TKE) is also derived. In the center of tip vortex and hub vortex region, high TKE concentration is observed. In addition, a time-averaged vector field is also measured and compared with phase-averaged vector field.

Effect of Modified High-heels on Metatarsal Stress in Female Workers

  • Kim, Kwantae;Peng, Hsien-Te
    • 한국운동역학회지
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    • 제29권3호
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    • pp.197-204
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    • 2019
  • Objective: The purpose of this study was to identify the effect of high-heels (HH) modification on metatarsal stress in female workers. Method: Seven females who work in clothing stores ($heights=160.4{\pm}3.9cm$; $weights=47.4{\pm}4.1kg$; $age=31.3{\pm}11.1yrs$; $HH\;wear\;career=8{\pm}6.5yrs$) wore two types of HH (original and modified). The modified HH had been grooved with 1.5 cm radius and 0.2 cm depth around the first metatarsal area inside of the shoes using the modified shoe-last. Participants were asked to walk for 15 minutes on a treadmill and to stand for 10 minutes with original and modified HH, respectively. Kinetics data were collected by the F-scan in-shoe system. After each test, participants were asked to rate their perceived exertion using the Borg's 15-grade RPE scale and interviewed about their feeling of HH. Nonparametric Wilcoxon signed-rank test and effect size (Cohen's d) were used to determine the difference of the variables of interest between the original and modified HH. Results: In the present study, modified HH of the peak contact pressure of 1st metatarsal (PCP) left, PCP right, pressure time integral (PTI) left, peak pressure gradient (PPG) left during standing and PPG right during walking are greater than original HH. And even it didn't show statistically significant, the average in all pressure values of modified HH showed bigger than original HH. It surmised to be related to awkward with modified HH. Even though they said to feel the comfortable cause of big space inside of HH in the interview, they seemed to be not enough time to adapt with new HH. So their walking and standing postures were unstable. Conclusion: Modified the fore-medial part of HH can reduce the stress in the first metatarsal head and big toe area during standing and walking.

Analysis on Heating Effects of the Vertical Type Geothermal Heat Pump System

  • Kang, Youn Ku;Ryou, Young Sun;Jang, Jae Kyung;Kim, Young Hwa
    • Journal of Biosystems Engineering
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    • 제39권2호
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    • pp.69-75
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    • 2014
  • Purpose: This paper is aimed at analyzing the heating performance of the vertical closed loop type Geothermal Heat Pump System (GHPS) distributing the farm site and providing basic data of the GHPS. Method: Seedling greenhouse heating was made from October 2012 to May 2013. The seedling greenhouse was divided into 4 sectors (A, B, C and D zone, total $3,300m^2$) with different temperatures. It was heated from 5PM to 8AM, and during the night the greenhouse was covered by non-woven fabric thermal curtains along the upper 2m of the greenhouse for temperature maintenance. In order to analyze the heating performance of the GHPS, power consumption and operating time of the GHPS, inlet and outlet water temperature of the condenser, temperatures of each zone of the greenhouse, and ambient temperature were measured. Results: When operating only one heat pump unit, heat generated in the condenser decreased as the experiment progressed and power consumption increased correspondingly. However, the heating coefficient of performance decreased from 3.3 to 2.0 rapidly. Also, when operating two heat pump units, heat generated in the condenser decreased and power consumption increased. Heating coefficient of performance decreased from 4.5 to 3.7 rapidly. When the set temperature of the greenhouse was $13.7{\sim}20.1^{\circ}C$ and minimum ambient temperature was $-20.8{\sim}4.8^{\circ}C$, the annually accumulated heat and power consumption were 520,623 kW, 142,304 kW, respectively. Conclusion: When the set temperature of the greenhouse was $13.7{\sim}20.1^{\circ}C$ and the minimum ambient temperature was $20.8{\sim}4.8^{\circ}C$, the annually accumulated heat and power consumption were 520,623 kW, 142,304 kW, respectively. When operating only one heat pump unit, the heating COP was 2.0~3.3, and when operating 2 heat pump units, it was 3.7~4.5. If several heat pumps are installed in one GHPS, it is suggested that all heat pumps be operated except in special cases. Because the scale of the water pumps are set to the scale of when all heat pump units are operating, if even one unit is not operating, the power consumption will increase. That becomes the cause of COP decrease.

The First Crustal Refraction Survey in the Korean Peninsula

  • Jung Mo Lee;Wooil Moon;Chang-Eob Baag;Heeok Jung;Ki Young Kim;Bong Gon Jo;Woohan Kim;Sung Kyun Kim
    • IUGG한국위원회:학술대회논문집
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    • IUGG한국위원회 2003년도 정기총회 및 학술발표회
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    • pp.15-15
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    • 2003
  • The first crustal refraction survey in the Korean Peninsula was carried out over the survey line connecting Seosan-Yeongdong-Kyeongiu on Dec. 15, 2002. The total length of the survey line was about 300 Km and 198 portable seismometers were deployed with approximately 1.5-km interval. The survey line itself was geologically important since it was almost normal to the so-called Sino-Korean structural trend. Two shots, one at Seosan (west end point) and the other at Yeongdong (mid-point), were exploded. They were 100-m deep drill well explosions. The Seosan shot consisted of a ton emulsion type explosive, while Youngdong consisted of 500 kg one. Both shots generated signals with good S/N ratios to the farthest receivers. Seismic signals were recorded by 195 receivers out of 198 ones. Although the originally planned Kyeongju shot (east end point) could not be exploded due to public discontent, the experiment was evaluated very successful. First breaks in all recorded traces were picked up and two preliminary analyses were carried out. The one is conventional flat layer analysis and the other was refraction tomographic analysis. The one resulted in average 32-km thick two-layer crust and the underlying mantle with 8.05-km/s P-velocity. The top crust layer with 3.86 kw/s P-velocity was 2.5-km thick and the lower crust layer with 6.0l km/s P-velocity was 29.5-km thick. The other resulted in a velocity cross-section. The confidence level of the velocity cross-section could not be evaluated at this time because only two shot were exploded. Detailed analyses such as surface wave dispersion are on going. Continuing crustal scale refraction surveys are planned in Korea.

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