• Title/Summary/Keyword: Unequal Distribution

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Quality Characteristics of Korean Red Ginseng Powder with Different Milling Methods (분쇄방법에 따른 고려홍삼분말의 품질특성)

  • 서창훈;이종원;도재호;김나미;양재원;장규원
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.32 no.3
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    • pp.370-374
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    • 2003
  • Cell cracking method using a non-collision was evaluated for the possibility of new red ginseng grinding technique. Based on particle size distribution analysis by 1size shaker, the ratios of 100 mesh penetrated particles were 94.9% for hammer mill (group A) and 95.6% for cell crack (group B). The ratio of 120 mesh penetrated particle of group A was higher than that in group B. The particle size distributions for 100 mesh non-penetrated Powder between 2 groups were not significantly different, and particle size distribution analysis by laser scattering analyzer showed that the particle size ranges were 0.77~128.07 ${\mu}{\textrm}{m}$ for group A and 4.24~180.07 ${\mu}{\textrm}{m}$ for group B. The Particle size distribution in group A was more broad than that in group B. The mean particle size in group B was larger than that in group A, while the standard deviation of particle size distribution in group B was less than that in group A. Structural surface characteristics, in group A, particle size distribution was broad and the distribution curve was amorphous. The structure of individual particles was similar to unequal stone which was roughly grinded and had soft cotton-like surface. In the contrary, in group B, particle size distribution was relatively narrow and also individual size particles were ubiquitously distributed. The structure of individual particles was unequal cut stone shape.

Analysis on Current Distribution of Four-Layer HTSC Power Transmission Cable with a Shield Layer

  • Lim Sung-Hun
    • Journal of Electrical Engineering and Technology
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    • v.1 no.3
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    • pp.308-312
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    • 2006
  • The inductance difference between conducting layers of high-Tc superconducting (HTSC) power transmission cable causes the current sharing of each conducting layer to be unequal, which decreases the current transmission capacity of HTSC power cable. Therefore, the design for even current sharing in HTSC power transmission cable is required. In this paper, we investigated the current distribution of HTSC power cable with a shield layer dependent on the pitch length and the winding direction of each layer. To analyze the effect of the shield layer on the current sharing of the conducting layers of HTSC power cable, the current distribution of HTSC power cable without a shield layer was compared with the case of HTSC power cable with a shield layer. It could be found through the analysis from the computer simulations that the shield layer of HTSC power cable could be contributed to the improvement of current distribution of conducting layers at the specific pitch length and the winding direction of conducting layer. The result and discussion for the current distribution calculated for HTSC power transmission cable with a shield layer were presented and compared with the cable without a shield layer.

Change in Spatial Distribution of Photovoltaic Power Generation (태양광 발전의 분포 변화: 시군구 단위에서의 분석)

  • Chung Sup Lee;Kang-Won Lee;Sang-Hyun Chi
    • Journal of the Economic Geographical Society of Korea
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    • v.25 no.4
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    • pp.484-498
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    • 2022
  • The purpose of this study is to analyze the location, distribution and its change of photovoltaic power generation in the scale of municipality(Si-Gun-Gu). First the distribution of photovoltaic power generation was analyzed in 2020, and second, from 2017 to 2021, we tracked the increase in capacity of power generation facilities in each Si-Gun-Gu. As a result, the distribution and increase of photovoltaic power generation were concentrated in some regions and the unequal distribution of photovoltaic power generation has been identified through Gini coefficient.

An Estimating Reliability of Machine Elements Subjected to Fluctuating Load Considering Static and Dynamic Allowable Safety Factors (변동하중시 정ㆍ동적 허용안전계수를 고려한 기계부품의 신뢰성 평가)

  • 양성모;강희용;김강희
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.4
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    • pp.51-57
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    • 1998
  • It is common to assume identical allowable safety factors in static strength defined by mean stress and in fatigue, defined by stress amplitude. Under the load with asymmetrical cycles the safety factor is not the same. In this paper, with the consideration of unequal allowable safety (actors a general method for estimating fatigue reliability of a machine element under a combined state of stress is derived based on the theory proposed by Prof. Kececioglu and a normal distribution. The calculation of fatigue reliability fur limited life is discussed with example.

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Bayesian Method on Sequential Preventive Maintenance Problem

  • Kim Hee-Soo;Kwon Young-Sub;Park Dong-Ho
    • Communications for Statistical Applications and Methods
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    • v.13 no.1
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    • pp.191-204
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    • 2006
  • This paper develops a Bayesian method to derive the optimal sequential preventive maintenance(PM) policy by determining the PM schedules which minimize the mean cost rate. Such PM schedules are derived based on a general sequential imperfect PM model proposed by Lin, Zuo and Yam(2000) and may have unequal length of PM intervals. To apply the Bayesian approach in this problem, we assume that the failure times follow a Weibull distribution and consider some appropriate prior distributions for the scale and shape parameters of the Weibull model. The solution is proved to be finite and unique under some mild conditions. Numerical examples for the proposed optimal sequential PM policy are presented for illustrative purposes.

Improvement of Thermal Enviromental by Two Air Out in Hot Air Heating (이중 취출구에 의한 온풍난방시의 열환경 개선)

  • Jang, In-Seong;Kim, J.S
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.33 no.3
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    • pp.209-217
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    • 1997
  • The objective of this paper is to improve a discomfort caused by the unequal airflow and vertical temperature difference by buoyancy of the supplied hot air in the conventional hot air heating system. In order to the model experiment we manufactured the hot air heater with two air outlet and a model room. We observed the temperature, velocity and airflow distribution and calculated values of PMV and PPD using mean value of central verticality section's air temperature and velocity. We could improve distribution of vertical temperature and velocity at the central section of the model room owing to correlation of hot air of two air outlet.

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Characteristics Analysis of BLOC Motor with C type Permanent Magnet (C type 영구자석을 갖는 BLDC 모터의 특성 해석)

  • Rhyu, S.H.;Im, T.B.;Chung, J.K.;Ha, K.S.;Lee, S.H.;Lee, B.H.
    • Proceedings of the KIEE Conference
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    • 2001.04a
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    • pp.50-52
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    • 2001
  • The BLDC(Brushless DC) motor with the permanent magnet has many merits such as high efficiency and efficiency. These characteristics of the BLDC motor makes them one of the most popular motors in the world today. The C type ferrite magnet is many used in BLDC motor for high performance, especilly low price. Many papers have been written on the analysis of the BLDC motor with C type ferrite magnet. But, most of these target models are contained symmetric distribution of permanent magnet. In this paper, investigations are made on different distribution of permanent magnets for a understanding of the effects of unequal permanent magnet location on the unbalanced cogging torque. Motor torque and cogging torque are obtained by using the 2 dimensional finite element method.

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Clustering Algorithm Considering Sensor Node Distribution in Wireless Sensor Networks

  • Yu, Boseon;Choi, Wonik;Lee, Taikjin;Kim, Hyunduk
    • Journal of Information Processing Systems
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    • v.14 no.4
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    • pp.926-940
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    • 2018
  • In clustering-based approaches, cluster heads closer to the sink are usually burdened with much more relay traffic and thus, tend to die early. To address this problem, distance-aware clustering approaches, such as energy-efficient unequal clustering (EEUC), that adjust the cluster size according to the distance between the sink and each cluster head have been proposed. However, the network lifetime of such approaches is highly dependent on the distribution of the sensor nodes, because, in randomly distributed sensor networks, the approaches do not guarantee that the cluster energy consumption will be proportional to the cluster size. To address this problem, we propose a novel approach called CACD (Clustering Algorithm Considering node Distribution), which is not only distance-aware but also node density-aware approach. In CACD, clusters are allowed to have limited member nodes, which are determined by the distance between the sink and the cluster head. Simulation results show that CACD is 20%-50% more energy-efficient than previous work under various operational conditions considering the network lifetime.

Spatial Distribution of Information Related Occupation and Its Regional Difference in Korea (우리나라 정보관련직종의 공간적 분포와 지역화 격차에 관한 연구)

  • 이희연
    • Journal of the Korean Regional Science Association
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    • v.9 no.1
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    • pp.3-23
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    • 1993
  • In this paper the prevailing geography of the information sector, fousing on its occupatonal dimension, is examined. The purposes of this paper are to analyze the labor force share of information occupation workers at each special city and region, to compare the inter-regional distribution of information workforce and to analyze regional share of information occupations in manufacturing industry. Spatial pattern of size and occupational composition of information sector shows a core-periphery disparity. There is a clear evidence of Seoul's dominance of the information economy, particularly such as scientific and technical, consultative services, management and process control function. Also the distribution of information workers in manufacturing industry over space was polarized than is the case for total manufacturing employment and noninformation workers. Therefore Korean information economy is marked by a highly articulated spatial division of labor within individual industry, which can be attributed to the locational characteristics of information intensive industries and industrial composition of regional economy. From the results of this study, information employment prospects among regions of Korea would reinforce the unequal geography of job opportunity. In this light, regional policy efforts should be given to the improvement of information infrastructure to facilitate new computer-based service products and process in peripheral regions.

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Analytical Prediction of Bearing Life and Load Distribution for Plugin HEV (플러그인 HEV용 베어링 수명 및 응력분포의 분석예측)

  • Zhang, Qi;Kang, Jae-Hwa;Yun, Gi-Baek;Lyu, Sung-Ki
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.11 no.5
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    • pp.1-7
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    • 2012
  • The transportation is almost dependent on a single fuel petroleum with transportation energy dilemma. Hybrid Electric Vehicle(HEV) technology holds more advantages on efficiency improvements for petroleum consumption at the transportation. And bearing is recognized as the important component of gearbox. Gearboxes for HEV transmission have been ensured the highest reliability over some years in withstanding high dynamic loads. At the same time, the demands of lightweight design and cost minimization are required by thought-out design, high-quality material, superior production quality and maintenance. In order to design a reliable and lightweight gearbox, it is necessary to analyze bearing rating life methods between standard and different bearing companies with calculation methods for modification factors. In this paper, the influence of life time of bearings will be pointed out. Bearing contact stress and load stress distribution of HEV gearbox are obtained and compared with Romaxdesigner and BearinX. And the unequal wear of the left bearing for the gearbox intermediate shaft is investigated between simulation and test.