• Title/Summary/Keyword: Lagging

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Optimal Forecasting for Sales at Convenience Stores in Korea Using a Seasonal ARIMA-Intervention Model (계절형 ARIMA-Intervention 모형을 이용한 한국 편의점 최적 매출예측)

  • Jeong, Dong-Bin
    • Journal of Distribution Science
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    • v.14 no.11
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    • pp.83-90
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    • 2016
  • Purpose - During the last two years, convenient stores (CS) are emerging as one of the most fast-growing retail trades in Korea. The goal of this work is to forecast and to analyze sales at CS using ARIMA-Intervention model (IM) and exponential smoothing method (ESM), together with sales at supermarkets in South Korea. Considering that two retail trades above are homogeneous and comparable in size and purchasing items on off-line distribution channel, individual behavior and characteristic can be detected and also relative superiority of future growth can be forecasted. In particular, the rapid growth of sales at CS is regarded as an everlasting external event, or step intervention, so that IM with season variation can be examined. At the same time, Winters ESM can be investigated as an alternative to seasonal ARIMA-IM, on the assumption that the underlying series shows exponentially decreasing weights over time. In case of sales at supermarkets, the marked intervention could not be found over the underlying periods, so that only Winters ESM is considered. Research Design, Data, and Methodology - The dataset of this research is obtained from Korean Statistical Information Service (1/2010~7/2016) and Survey of Service Trend of Korea Statistics Administration. This work is exploited time series analyses such as IM, ESM and model-fitting statistics by using TSPLOT, TSMODEL, EXSMOOTH, ARIMA and MODELFIT procedures in SPSS 23.0. Results - By applying seasonal ARIMA-Intervention model to sales at CS, the steep and persisting increase can be expected over the next one year. On the other hand, we expect the rate of sales growth of supermarkets to be lagging and tied up constantly in the next 2016 year. Conclusions - Based on 2017 one-year sales forecasts for CS and supermarkets, we can yield the useful information for the development of CS and also for all retail trades. Future study is needed to analyze sales of popular items individually such as tobacco, banana milk, soju and so on and to get segmented results. Furthermore, we can expand sales forecasts to other retail trades such as department stores, hypermarkets, non-store retailing, so that comprehensive diagnostics can be delivered in the future.

NUMERICAL STUDY ON THE UNSTEADY FLOW PHYSICS OF INSTECTS' FLAPPING FLIGHT USING FLUID-STRUCTURE INTERACTION (FSI를 활용한 2차원 곤충날개 주위 유동장 해석)

  • Lee, K.B.;Kim, J.H.;Kim, C.
    • 한국전산유체공학회:학술대회논문집
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    • 2009.11a
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    • pp.151-158
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    • 2009
  • To implement the insects' flapping flight for developing flapping MAVs(micro air vehicles), the unsteady flow characteristics of the insects' forward flight is investigated. In this paper, two-dimensional FSI(Fluid-Structure Interaction) simulations are conducted to examine realistic flow features of insects' flapping flight and to examine the flexibility effects of the insect's wing. The unsteady incompressible Navier-Stokes equations with an artificial compressibility method are implemented as the fluid module while the dynamic finite element equations using a direct integration method are employed as the solid module. In order to exchange physical information to each module, the common refinement method is employed as the data transfer method. Also, a simple and efficient dynamic grid deformation technique based on Delaunay graph mapping is used to deform computational grids. Compared to the earlier researches of two-dimensional rigid wing simulations, key physical phenomena and flow patterns such as vortex pairing and vortex staying can still be observed. For example, lift is mainly generated during downstroke motion by high effective angle of attack caused by translation and lagging motion. A large amount of thrust is generated abruptly at the end of upstroke motion. However, the quantitative aspect of flow field is somewhat different. A flexible wing generates more thrust but less lift than a rigid wing. This is because the net force acting on wing surface is split into two directions due to structural flexibility. As a consequence, thrust and propulsive efficiency was enhanced considerably compared to a rigid wing. From these numerical simulations, it is seen that the wing flexibility yields a significant impact on aerodynamic characteristics.

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The Voluntary Assurance of Quality by Contractors in the Construction Phase (건설 공사단계에서 수급자 중심의 품질확보방안)

  • Cha, Sang-Ho;Lee, Sang-Beom
    • Journal of the Korea Institute of Building Construction
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    • v.11 no.3
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    • pp.292-300
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    • 2011
  • The construction industry in Korea has seen significant improvements in quality management techniques, driven by the dramatic development of new technology through Manhattanization and enlargements, but compared with technical development, the level of building quality improvement is still lagging behind. In the meantime, as the interest in construction quality soars due to changes in user consciousness, the level of quality that is being demanded is rising. The government has reinforced quality systems by implementing responsible supervision requirements and granting overseas companies permission to enter the supervision business in Korea, and private sector companies also are attempting quality improvement through quality assurance approaches like the preliminary qualification screening system and ISO 9000 series. But currently, building constructions are done only according to the construction specifications of project owners, whose design, materials and construction methods are already decided, and do not leave any necessity or opportunity for technical developments for the quality improvement of contractors. Therefore, in this study, a work process and system improvement plan for payment regulations is proposed, with which contractors can secure quality voluntarily in the building construction phase.

Carbon Reduction Effect of Traffic Operational Methods Itemized in National Project for Advanced Traffic Operation and Management (교통운영체계선진화의 탄소감축 효과 연구)

  • Kim, Wonchul;Kim, Jin-Tae
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.32 no.1D
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    • pp.1-11
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    • 2012
  • The presidential council on national competitiveness and the national police agency have initiated a national project to refresh the road traffic control and operation systems to increase operational efficiency at signalized intersections. It would reduce the number of stops and delay of vehicles at intersections and thus mitigate congestion and emission. Although significant reduction of carbon is expected as a consequential result, such effects has yet been studied since traffic operation was behind of interest in the field of green transportation where planning was mainly involved. This paper delivers the macroscopic effects of carbon reduction of the selected items of the national project: the ones managed by the police agency. The results showed that the studied items yield significant reduction of carbon: pedestrian push button operation, flashing signal operation, progression, lagging left turns, permitted left turn, and actuated left-turn operation would reduce 12.31%, 3.27%, 2.44%, 0.97%, 0.81%, and 0.72% of the total amount of carbon emitted a year in a whole transportation sector, respectively.

A Lecture Book on Traditional Korean Medicine in the Period of Japanese Occupation, 『Eihak Gangseupseo(醫學講習書)』 - focused on its preface, epilogue and reference books (일제강점기의 한의학 교재 중 하나인 『한방의학강습서(漢方醫學講習書)』 - 서문과 발문(跋文)의 번역과 인용서적의 분석을 중심으로)

  • Jo, Hak-jun
    • The Journal of Korean Medical History
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    • v.23 no.1
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    • pp.77-104
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    • 2010
  • In July 2008, I obtained a copy of "Hanbang Eihak Gangseupseo" through Uibangseowon. It was recorded that the book was compiled by Seong Ju-bong and reviewed by Ji Seok-young. According to previous studies, this book was the lecture book that was used in teaching Traditional Korean Medicine in Daejeon, Chungcheongnam-do. This book gave insight to the system and curriculum of the school for Traditional Korean Medicine in Daejeon, Chungcheongnam-do. It also exhibited the academic characteristics of Traditional Korean Medicine in the Period of Japanese Occupation and the medical viewpoint of Seong Ju-bong. The summary is as follows: First, an independent School for Traditional Korean Medicine was run in Daejeon, Chungcheongnam-do, with reasonable curriculums and systematic textbooks. Second, the medical viewpoint and treatment methods of Huang Yuan-Yu of Qing Dynasty was actively introduced. Then it was reorganized for the society and stimulated the progress of Traditional Korean Medicine. Third, while absorbing Chinese Medicine, it still inherited our heritage of Traditional Korean Medicine Especially, Seong Ju-bong's original opinions and clinical experiences are shown in surgery, gynecology and pediatrics. Fourth, in a break from the past, when Chinese culture could not be introduced due to diplomatic problems between Joseon and Qing, efforts were made to overcome limitations of lagging behind by adopting and educating Warm Disease study. Fifth, while working side by side with Ji Seok-young who introduced the modern Western Medicine through vaccination, it still searched for a traditional Korean medical treatment for chickenpox. I hope that the report of my findings through reading "Eihak Gangseupseo" could make up for the fact that the medical history during the colonial period is scarce.

Design of an Elastomeric Bearing for a Helicopter Rotor Hub by Non-linear Finite Element Method (비선형 유한요소법을 이용한 헬리콥터 로터허브용 탄성체베어링 설계)

  • Kim, Hyun-Duk;Yoo, Si-Yoong;Park, Jung-Sun
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.38 no.6
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    • pp.612-619
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    • 2010
  • In this paper, an elastomeric bearing for a helicopter rotor hub is designed using nonlinear finite element method. The elastomeric bearing is the main component of the helicopter rotor hub that acts as a hinge to three motions(flapping, lagging and pitching) of rotor blade. The elastomeric bearing consists of rubber and metal plates. The stiffness design of the elastomeric bearing is important because elastic deformation of rubber is served to hinge. Accordingly, the elastomeric bearing is designed to satisfy the stiffness requirements for rotor hub bearing. In this study, a FE model generation algorithm is developed and stiffness characteristic of a rubber plate is analyzed for an efficient design of the spherical elastomeric bearing. It is proven that the elastomeric bearing satisfies stiffness requirements of the spherical bearing for a helicopter rotor hub.

Replication origin (ori) of R-plasmid pSBK203 Isolated from Staphylococcus aureus DHI (Staphylococcus aureus DH1에서 분리한 R-plasmid pSBK203상의 복제개시 부위 ori에 관한 연구)

  • Min, Kyung-Il;Byeon, Woo-Hyeon
    • Korean Journal of Microbiology
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    • v.32 no.3
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    • pp.186-191
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    • 1994
  • The origin of the leading strand replication (ori) and of lagging strand replication (M-O) of R-plasmid pSBK203 was identified and its base sequence was determined. About 50 bp of ori sequence residues overlapped with the structural gene of rep. Sequence comparison reveals that pSBK-ori shares obvious identities with those of pT181 family and consists of two regions, one is conserved and the other is variable region. Of two palindrome sequence located one after another in upstream region of rep gene, palA' instead of palA which shares sequence homology with diverse family of plasmids such as pOX6, pC194, and pE194 seems to act as a signal for conversion of primarily replicated ssDNA to dsDNA (minus origin (M-O)).

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Sympathetic Nerve Function to Electrical Response of Ryodoraku Point and Disarrangement of its Meridian Location on the Anatomical Viscera Exclude the Association between Ryodoraku Theory and Meridian Principle (양도점의 전기적 반응에 대한 교감신경작용과 경락 배열과 실질장기의 불일치는 양도락의 경락 관련성을 배제한다.(위 운동장애형 기능성 소화불량증 환자의 양도점 H4,5,6의 반응을 중심으로))

  • Yoon, Sang-Hyub
    • The Journal of Internal Korean Medicine
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    • v.32 no.2
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    • pp.259-277
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    • 2011
  • Objectives : The purpose of this study was to investigate two subjects: the diagnostic value of bilateral lowering of electrical activity at point H4,5,6 of Ryodoraku and the mechanism for Ryodoraku phenomena. Methods : Electrical activities of Ryodoraku test and electrogastrography recorded simultaneously and monitored continuously from 16 cases of functional dyspeptic patients were collected and their variations were grouped by the topics of discussion which were peculiarity, stability, lagging, alterability, and anomaly. Ryodoraku recordings obtained from 6 patients with different gastrointestinal diseases and 1 normal healthy person were used as control. The results are discussed with Nakatani's suggestion, theory of sympathetic nerve and Meridian Principle, respectively. Finely, coincidence of stomach arrangement between anatomy and meridian system in Ryodoraku was also evaluated. Results : Time-course variation showed a regular relationship between the typical pattern of Ryodoraku at point H4,5,6 and gastric myoelectrical activity. However, an irregular relationship and atypical pattern of Ryodoraku occasionally appeared. A literature search suggested that electrical response at the Ryodoraku point H4,5,6 may be dependent on an afferent sympathetic spinal reflex transmitted from the stomach. However, there was no evidence for making clear whether bilateral lowering of electrical activity at this point was induced by hypofunction of local sympathetic nerve in the skin itself or of signals transmitted from the gastric sympathetic nerve or not. The coincidence of 19% could not provide a visceral arrangement of the stomach between anatomy and meridian systems. Conclusions : Bilateral lowering of electrical activity at Ryodoraku point H4,5,6 has value as a diagnostic index for gastric dysmotility of functional dyspepsia. This phenomenon is associated with spinal reflex transmitted from the afferent sympathetic nerve in the stomach but not that of meridian function.

A Study on Application of Port Hinterland by a Space Port City Interface Characteristics (항만도시 인터페이스 공간특성에 의한 항만배후단지 활용방안)

  • Hwang, Sun Ah;Kim, Jong Gu;Hong, Ji Su
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.36 no.1
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    • pp.169-180
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    • 2016
  • The spaces of port and urban in a Port City have different space characteristics substantially, but those are required to be developed interdependently. Degradation and loss of the sense of place in the existing spaces caused by decline of natural function have an adverse effect on the revival of local economy as well as make worse image of the entire city. In some developed countries, therefore, many researches on the port spaces lagging behind the times due to changes of the characteristics and function of port spaces have been conducted continuously for a long time. This study aims at seeking a device how the domestic hinterland could be utilized as efficient spaces having the characteristics of outskirts space and port city interface through the application of characteristics of the interface space of port city, capable of playing a role as buffer zone between the port space and the city space.

A Comparative Study on Layout of the National Language Textbooks in Korea and China - Focusing on the 3rd and 4th of Elementary School (한·중 국어 교과서 레이아웃 비교 연구 초등학교 3, 4학년 국어 교과서를 중심으로)

  • Hou, Hongwu;Oh, Chi-Gyu
    • The Journal of the Korea Contents Association
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    • v.18 no.4
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    • pp.234-244
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    • 2018
  • This study is a comparative analysis of the layout of Korean textbooks in Korea and China in the 3rd and 4th grades. According to the times, textbooks are constantly changing and developing in various fields from contents to design. But a tool for learning remains was unchanged. Especially, the textbooks of elementary school are aimed at conveying basic knowledge by inducing interest of children. So the layout design is important. By combining typography, illustration, color, and margins in a well-balanced and uniform design, the contents of textbooks can be well transmitted to children. Therefore, this study has recognized the importance of layout and tried to suggest improvement by grasping the lack of Chinese textbook which is lagging behind design.