• 제목/요약/키워드: group efficiency

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사질토 지반에서 군말뚝의 수평거동에 관한 연구 (Lateral Behavior of Group Pile in Sand)

  • 김영수;김병탁
    • 한국지반공학회논문집
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    • 제16권1호
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    • pp.117-129
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    • 2000
  • 본 논문은 균질 및 비균질 지반에서의 군말뚝수평거동에 관하여 고찰하였다. 본 연구는 군말뚝수평거동에 대한 말뚝중심간격, 말뚝 배열, 말뚝 중심 간격비, 말뚝 선단 구속조건, 편심하중 그리고 지반조건의 영향들에 관하여 실험적인 연구를 수행하였다. 주동말뚝에서의 군말뚝 효율과 수평변위는 말뚝중심간격과 말뚝수에 상당히 의존함을 알 수 있다. 말뚝중심간격이 6D이고 $3\times3$배열 말뚝인 경우, 선단고정말뚝의 수평 지지력은 선단자유말뚝의 경우보다 40-100%크게 나타났다. 모형실험의 결과들에 근거하여, 군말뚝의 개개 말뚝이 단일말뚝과 동일하게 거동하는 말뚝 중심간격은 상대밀도 61.8%와 32.8%의 경우 6D 로 나타났으나, 상대밀도 90%의 조밀한 지반에서는 8D 간격으로 추정할 수 있다. 본 연구에서는 군말뚝 효율에 대하여 말뚝 중심간격, 말뚝 수, 그리고 지반상대밀도의 변수로 표현되는 실험식을 제안하였다. 3$\times$3 배열의 군말뚝에서 앞행(lead row) 말뚝의 하중 분담율은 말뚝 중심간격 3D인 경우에 41.6%-52.4% 정도 그리고 6D인 경우에 34%-40%정도로 나타났다. 군말뚝에서 중첩효과(shadowing effect)는 하중 직각방향보다는 하중 재하방향에서 더 크게 발생하였다.

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소매유통업의 효율성 분석에 관한 연구 (An analysis of retail business efficiency in Korea)

  • 김순홍;유병국
    • 유통과학연구
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    • 제12권4호
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    • pp.23-30
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    • 2014
  • Purpose - The purpose of this study is to analyze the efficiency of retail businesses by dividing domestic retailers into discount stores, super supermarkets (SSMs), and department stores. It suggests retail-business investment strategies by using data environment analysis (DEA) to analyze how input elements such as store area, parking lot area, number of employees, and sales management expenses for the convenience of customers positively affect business performance measurements such as sales and visiting customers per day. Research Design, Data, and Methodology - The DEA model calculates a ratio of the weighted mean of various inputs to the weighted mean of various outputs and measures the efficiency of a specific decision making unit (DMU). The study included 19 companies (five discount store DMUs, ten SSM DMUs, and four department store DMUs). Because the business elements and sizes of retail store DMUs used in this analysis are different, average per-store input and output variables were used. Data were collected from "The Yearbook of Retail Industry in Korea (2012)." DEA analysis was used to determine differences in efficiency among discount stores, SSMs, and department stores in terms of the business elements of each retail business. It was also used to determine what business elements were excessively invested in by comparing and analyzing efficiency by business elements using SPSS software's ANOVA (Analysis of Variance). Results - The CCR and BCC efficiency analysis found that the efficiency of discount stores is low. We believe that the saturation state of discount stores is a major factor. The ANOVA analysis confirms the VRS hypothesis with a statistically significant difference among the three groups, based on an analysis confidence interval of 95%. CRS and SE were not found to be significantly different among the three groups. As for the post hoc test, which concretely shows differences by group, the Scheffe's multiple comparison analysis test found the average differences between group 1 (discount stores) and group 2 (SSM) to be statistically significant. Conclusions - The DEA efficiency analysis implies that investment in input elements, including store area, parking lot area, and sales management expenses, were excessive in the case of discount stores, while SSMs need to invest more in promotion activities such as gifts, events, and coupons for customer management. Department stores have found that small companies invest excessively in input elements. Department stores need to invest in differentiated shopping mall complexes. This study was limited in acquiring statistical data; various input variables which might have shown more secure customer management and promotional expenses could not be applied. As the study was limited in various aspects of the efficiency analyses because financial analyses of the companies and of causal relationships, including satisfaction and loyalty of visiting customers, were not done, these aspects will be examined in the next study.

차량 전장 부품 특성이 MDPS 조타 토크에 미치는 영향 (Effects of Vehicle Electric Components on the Steering Input Torque)

  • 조현석;이병림;장세현;박영대;김민준
    • 한국자동차공학회논문집
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    • 제22권6호
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    • pp.113-119
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    • 2014
  • For the robust design of Motor Driven Power Steering (MDPS) systems, it is important to consider energy efficiency from every aspect such as system configuration and current flow, etc. If design optimization is not considered, it has many problems on a vehicle. For example, when evaluating steering test, particularly the Catch-up test which turning the steering wheel left or right quickly, steering effort should be increased rapidly. Also a vehicle might have poor fuel efficiency. In this study, it is calculated energy consumption for each component of the steering system and analyzed factors of energy consumption. As a result, this paper redefines a method to estimate steering input torque using characteristics of vehicle electric components and then conducts an analysis of contribution for the Catch-up.

A Review of Strategy to Capture Niche Marketing of HTS Power Distribution Cable

  • Park, Sang-Bong;Nam, Kee-Young;Kim, Dae-Kyeong;Jeong, Seong-Hwan;Ryoo, Hee-Suk
    • KIEE International Transactions on Power Engineering
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    • 제4A권1호
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    • pp.11-17
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    • 2004
  • It becomes difficult and high in cost to construct new ducts and/or tunnels for power cables in domestic areas. This paper presents possible strategy of an HTS distribution cables for distributing electric power in local areas as niche marketing. Reflected were its important distinction such as system configuration, rationale, establishment of strategy and considerably high economical efficiency compared with present underground cables. In this paper, applicable important items by using HTS distribution cables in water pumping powerhouse and distribution substation as example objective regions were reviewed. Based on this, the following items on distribution HTS system are examined. (I)A review of constructing a model system to introduce high temperature superconducting distribution cables to objective areas is presented. (2)The strategy to capture HTS distribution cable in water pumping powerhouse and distribution substation as niche marketing regions were reviewed. (3)In concrete, system configuration, rationale, establishment of strategy and considerably high economical efficiency are reviewed between existing cable and HTS one.

다양한 발효균주를 이용한 인삼패독산의 생물 전환 성분의 정량 분석 (Quantitative Analysis of Bioconversion Constituents of Insampeadock-san Using Various Fermented Bacteria)

  • 이광진;구민정;노주환;정필문;마진열
    • 약학회지
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    • 제57권3호
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    • pp.167-172
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    • 2013
  • Insampaedoksan (IS) is the decoction of medicinal herbs, which was commonly used for anti-inflammatory and anti-pyretic in the Korean traditional medicine (KTM). Several studies on improving efficiency or searching new efficiency by fermenting traditional herbal medicines are recently in progress. The bioconversion has been conducted on IS using various bacteria. Liquiritin, ferulic acid, hesperidin, liquiritigenin, and glycyrrhizin in IS before and after fermented IS were simultaneously analyzed. These compounds were qualitatively analyzed and quantitatively analyzed using the HPLC-DAD system. The identifications of liquiritin, ferulic acid, hesperidin, liquiritigenin and glycyrrhizin were achieved by comparing the HPLC retention time ($R_t$) and the UV absorption of five pure compounds in the IS. As a result, the increased constituents were identified to be liquiritin, liquiritigenin and glycyrrhizin, while the decreased constituent was ferulic acid and the constituent of hesperidin was similar to before and after fermentation. Insampeadock-san fermented by Lactobacillus plantarum KFRI 144 exhibited the most remarkable changes in all of fermentation.

계분 발효사료가 육계의 성장과 영양소 이용율에 미치는 영향 (Effects of Dietary Levels of Fermented Poultry Manure on the Growth and Nutrient Availability of Broiler Chicks)

  • 장윤호;김정우;김인호;김춘수
    • 한국가금학회지
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    • 제25권3호
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    • pp.147-155
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    • 1998
  • Dietary levels of fermented poultry manure(FPM) 0%, 5%, 10% and 20% were included in experimental diets. It is to examine the effects of diets containing different levels of FPM on the performance of broiler chicks, including the nutrient availabilities, compared with that of the commercial diet. In order to evaluate the nutritive value of FPM, feeding and metabolism trials were conducted with a total of 160 broiler chicks for a period of 4 weeks. Contents of CP, crude fat, crude ash, crude fiber and NFE of FPM were 19.43, 2.43, 15.44, 16.57 and 38.31 %, respectively. Although there were no statistical difference in the body weight gain among treatments, weight gain achieved by the group fed diets of 5% substitution of FPM was slightly better than others. The amount of feed intake was significantly higher for FPM included groups than for control group, especially in the group fed diets of 10% substitution of FPM. The feed efficiency tended to be better for the control group than the FPM groups. The feed efficiency tended to get worse as the levels of FPM increased. The digestibility of DM, CP and NFE tended to be similar among treatments, especially it was lower for the group fed diets of 20% substitution of FPM compared with that of another groups. In conclusion, up to 10% substitution of FPM to the diet can be utilized effectively as a broiler feed ingredient, without adversely affecting growth performance.

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A Study on the Initial Irreversible Capacity of Lithium Intercalation Using Gradually Increasing State of Charge

  • Doh, Chil-Hoon;Jin, Bong-Soo;Park, Chul-Wan;Moon, Seong-In;Yun, Mun-Soo
    • KIEE International Transactions on Electrophysics and Applications
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    • 제3C권5호
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    • pp.189-193
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    • 2003
  • Initial irreversible capacity (IIC) can be defined by means of the initial intercalation Ah efficiency (IIE) and the initial irreversible specific capacity at the surface (IICs) with the linear-fit range of the intercalation so as to precisely express the irreversibility of an electrode-electrolyte system. Their relationship was IIC = Qc - Q$_{D}$ = (IIE$^{-1}$ - 1) Q$_{D}$ + IICs in the linear-fit range of IIE. Here, Qc and Qd signify charge and discharge capacity, respectively, based on a complete lithium ion battery cell. Charge indicates lithium insertion to carbon anode. Two terms of IIE and IICs depended on the types of active materials and compositions of the electrode and electrolyte but did not change with charging state. In an ideal electrode-electrolyte system, IIE and IICs would be 100%, 0 mAh/g for the electrode and mAh for the cell, respectively. These properties can be easily obtained by the Gradual Increasing of State of Charge (GISOC).OC).

인삼의 엽, 경을 첨가한 식이중 영양소의 흡수율에 관한 연구 (Absorption Rate of Nutrients in the Diets supplemented with the Leaf or Trunk of Panax Ginseng in Rat)

  • 김성미;황우익;김상순
    • Journal of Ginseng Research
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    • 제7권1호
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    • pp.23-36
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    • 1983
  • This study was devised to observe the nutritional effects of the diets supplemented with the leaf or trunk in rats. The male albino rats (110 heads), Sprague-Dowley strain weighing 75g to 79g, were used as the experimental aninl mils. The animals were divided into twelve diet groups and maintained with corresponding diet for 40 days, and then sacrificed. The growth rate, the consumption and efficiency ratios of the food and protein, the absorption rates of carbohydrate, lipid and protein, and the utilization rates of energy were determined during the feeding term. The results obtained are summarized as follows: 1) The growth rate, the consumption and efficiency ratios of the food and protein in each experimental diet group added ginseng steamed leaf or trunk were higher than those in experimental group A which has the diet supplemented with ginseng raw leaf of trunk. 2) The absorption rates of the carbohydrate were above 96%, higher than those or the control group, But those of fat, protein and the utilization rate of energy in each experimental diet group were generally lower than those in the control group.

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노르딕 워킹과 일반 보행의 효율성 비교 분석 (Comparative Analysis of Nordic Walking and Normal Gait Based on Efficiency)

  • 김로빈;조준행
    • 한국운동역학회지
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    • 제20권4호
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    • pp.365-372
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    • 2010
  • The purpose of this study were to analyze the changes in kinematic and kinetic parameters and to find biomechanical benefits of Nordic Walking and normal gait performed under the same velocity. Nine participants(age: $26.73{\pm}3.28$ year, height: $182.45{\pm}4.62\;cm$, weight: $76.59{\pm}6.84\;kg$) was chosen. The velocity of gait was set by 5.75 km/h which was made by a Nordic Walking professional. The data were collected by using VICON with 8 cameras to analyze kinematic variables with 200 Hz and force platform to analyze kinetic variables with 2000 Hz. The results of this study were as follows. First, when compared with Normal gait, Nordic Walking group showed decreased Plantarflexion angle and ROM. Second, Nordic Walking group showed decreased knee flexion angle and ROM. Third, Nordic Walking group showed increased hip joint movement. Fourth, Nordic Walking group showed higher active GRF but decreased loading rate from delayed Peak Vertical GRF time and increased impulse. Fifth, Nordic Walking group showed longer ground contact time. Through this study, we found that Nordic Walking showed higher stability and efficiency during gait than normal gait and that Nordic Walking may help people who have walking difficulties.

Enhanced Photovoltaic Performance of Perovskite Solar Cells by Copper Chloride (CuCl2) as an Additive in Single Solvent Perovskite Precursor

  • Kayesh, Md. Emrul;Matsuishi, Kiyoto;Chowdhury, Towhid H.;Kaneko, Ryuji;Noda, Takeshi;Islam, Ashraful
    • Electronic Materials Letters
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    • 제14권6호
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    • pp.712-717
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    • 2018
  • In this letter, we have introduced copper chloride ($CuCl_2$) as an additive in the $CH_3NH_3PbI_3$ precursor solution to improve the surface morphology and crystallinity of $CH_3NH_3PbI_3$ films in a single solvent system. Our optimized perovskite solar cells (PSCs) with 2.5 mol% $CuCl_2$ additive showed best power conversion efficiency (PCE) of 15.22%. The PCE of the PSCs fabricated by $CuCl_2$ (2.5 mol%) additive engineering was 56% higher than the PSC fabricated with pristine $CH_3NH_3PbI_3$.