• Title/Summary/Keyword: Demand Dependency

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A Seat Inventory Management Model in the Presence of Dependent Demands (종속적 수요를 반영하는 좌석재고 할당 모형)

  • Kim, Sang-Won
    • Korean Management Science Review
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    • v.27 no.2
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    • pp.67-79
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    • 2010
  • When airlines sell the same seats on an air flight at different fares, demand for a fare class depends on demand for other fare classes due to demand dependency. Demand dependencies occur when customers will buy other fare class tickets if the originally requested fare were unavailable, or when customers postpone their purchase decisions in anticipation of reopening of the lower fare in the next period. Demand dependency as a result customer buying behavior has a considerable profit implication, which was ignored in many earlier studies. We investigate the impact of demand dependency on the optimal booking limits and the expected revenues under a single-period and a two-period setting. We show how to find optimal booking limits of the problem and provide numerical examples to illustrate the impact.

Representation of Design Constraints in Entity-Based Integrated Model (개체형 통합모델에서의 설계 구속조건의 표현)

  • 이창호;리차드쏘스;이리형
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1998.04a
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    • pp.191-198
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    • 1998
  • An entity-based integrated design model can be used to organize and represent information and activities involved in design. The model involves a number of product and process entities. Product entities describe design information, and process entities describe design activities. The relationships among entities Includes organizational, interaction, and sequence relationships. The paper focuses interaction relationships among design information. The interaction relationships can be represented as constraints. Types of constraints includes demand constraints, dependency constraints, and interaction constraints. The paper describes dependency and Interaction constraints. The concepts of representing and processing dependency and interaction constraints in an entity-based integrated design model are presented.

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Forecasting Modeling of Heavy Tail Typed Demand using Student's t-Copula Fitting in Supply Chain Management (Student's t-Copula 적합을 통한 Heavy Tail형 SCM 수요 데이터의 모델링 및 분석)

  • Kim, Taesung;Lee, Hyunsoo
    • Journal of Digital Convergence
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    • v.11 no.9
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    • pp.103-111
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    • 2013
  • As the demand-oriented management has been getting important in Supply Chain Management (SCM), various forecasting methods have been suggested including regression analyses. However, dependency structures among variables have been captured by a correlation coefficient, only. It results in inaccurate demand predictions. This paper suggests a new and effective forecasting modeling framework using student's t-copula function. In order to show overall modeling procedures framework, heavy tail typed numerical data and its copula estimations are provided. The suggested methodology can contribute to decrease the bullwhip effect and to stabilize volatile environment in a supply chain network.

Inelastic Hysteretic Characteristics of Demand Spectrum -Focused on Elasto Perfectly Plastic Model- (요구스펙트럼의 비탄성이력특성 -완전탄소성모델을 중심으로-)

  • 이현호
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2000.04a
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    • pp.367-374
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    • 2000
  • This study investigates the effect of hysteretic characteristics to the Inelastic Demand Spectrum (IDS) which was expressed by an acceleration(Sa) and a displacement response spectrum (Sd). Elasto Perfectly Plastic(EPP) model is used in this study and inelastic demand spectrum (Sa vs, Sd) are obtained from a given target ductility ratio. For a given target ductility ratio IDS can be obtained by using nonlinear time history analysis of single degree of system with forth five recorded earthquake ground motions for stiff soil site. The effect EPP model under demand spectrum is investigated by ductility factor and natural frequency. According to the results obtained in this study IDS has dependency on ductility factor and natural frequency.

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Analysis of Forestry Structure and Induced Output Based on Input - output Table - Influences of Forestry Production on Korean Economy - (산업관련표(産業關聯表)에 의(依)한 임업구조분석(林業構造分析)과 유발생산액(誘發生産額) -임업(林業)이 한국경제(韓國經濟)에 미치는 영향(影響)-)

  • Lee, Sung-Yoon
    • Journal of the Korean Wood Science and Technology
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    • v.2 no.4
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    • pp.4-14
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    • 1974
  • The total forest land area in Korea accounts for some 67 percent of the nation's land total. Its productivity, however, is very low. Consequently, forest production accounts for only about 2 percent of the gross national product and a minor proportion of no more than about 5 percent versus primary industry. In this case, however, only the direct income from forestry is taken into account, making no reference to the forestry output induced by other industrial sectors. The value added Or the induced forestry output in manufacturing the primary wood products into higher quality products, makes a larger contribution to the economy than direct contribution. So, this author has tried to analyze the structure of forestry and compute the repercussion effect and the induced output of primary forest products when utilized by other industries for their raw materials, Hsing the input-output table and attached tables for 1963 and 1966 issued by the Bank of Korea. 1. Analysis of forestry structure A. Changes in total output Durng the nine-year period, 1961-1969, the real gross national product in Korea increased 2.1 times, while that of primary industries went up about 1. 4 times. Forestry which was valued at 9,380 million won in 1961, was picked up about 2. 1 times to 20, 120 million won in 1969. The rate of the forestry income in the GNP, accordingly, was no more than 1.5 percent both in 1961 and 1962, whereas its rate in primary industries increased 3.5 to 5.4 percent. Such increase in forestry income is attributable to increased forest production and rise in timber prices. The rate of forestry income, nonetheless, was on the decrease on a gradual basis. B. Changes in input coefficient The input coefficient which indicates the inputs of the forest products into other sectors were up in general in 1966 over 1963. It is noted that the input coefficient indicating the amount of forest products supplied to such industries closely related with forestry as lumber and plywood, and wood products and furniture, showed a downward trend for the period 1963-1966. On the other hand, the forest input into other sectors was generally on the increase. Meanwhile, the input coefficient representing the yolume of the forest products supplied to the forestry sector itself showed an upward tendency, which meant more and more decrease in input from other sectors. Generally speaking, in direct proportion to the higher input coefficient in any industrial sector, the reinput coefficient which denotes the use of its products by the same sector becomes higher and higher. C. Changes in ratio of intermediate input The intermediate input ratio showing the dependency on raw materials went up to 15.43 percent m 1966 from 11. 37 percent in 1963. The dependency of forestry on raw materials was no more than 15.43 percent, accounting for a high 83.57 percent of value added. If the intermediate input ratio increases in any given sector, the input coefficient which represents the fe-use of its products by the same sector becomes large. D. Changes in the ratio of intermediate demand The ratio of the intermediate demand represents the characteristics of the intermediary production in each industry, the intermediate demand ratio in forestry which accunted for 69.7 percent in 1963 went up to 75.2 percent in 1966. In other words, forestry is a remarkable industry in that there is characteristics of the intermediary production. E. Changes in import coefficient The import coefficient which denotes the relation between the production activities and imports, recorded at 4.4 percent in 1963, decreased to 2.4 percent in 1966. The ratio of import to total output is not so high. F. Changes in market composition of imported goods One of the major imported goods in the forestry sector is lumber. The import value increased by 60 percent to 667 million won in 1966 from 407 million won in 1963. The sales of imported forest products to two major outlets-lumber and plywood, and wood products and furniture-increased to 343 million won and 31 million won in 1966 from 240million won and 30 million won in 1963 respectively. On the other hand, imported goods valued at 66 million won were sold to the paper products sector in 1963; however, no supply to this sector was recorded in 1963. Besides these major markets, primary industries such as the fishery, coal and agriculture sectors purchase materials from forestry. 2. Analysis of repercussion effect on production The repercussion effect of final demand in any given sector upon the expansion of the production of other sectors was analyzed, using the inverse matrix coefficient tables attached to the the I.O. Table. A. Changes in intra-sector transaction value of inverse matrix coefficient. The intra-sector transaction value of an inverse matrix coefficient represents the extent of an induced increase in the production of self-support products of the same sector, when it is generated directly and indirectly by one unit of final demand in any given sector. The intra-sector transaction value of the forestry sector rose from 1.04 in 1963 to 1, 11 in 1966. It may well be said, therefore, that forestry induces much more self-supporting products in the production of one unit of final demand for forest products. B. Changes in column total of inverse matrix coefficient It should be noted that the column total indicates the degree of effect of the output of the corresponding and related sectors generated by one unit of final demand in each sector. No changes in the column total of the forestry sector were recorded between the 1963 and 1966 figures, both being the same 1. 19. C. Changes in difference between column total and intra-sector transaction amount. The difference between the column total and intra-sector transaction amount by sector reveals the extent of effect of output of related industrial sector induced indirectly by one unit of final demand in corresponding sector. This change in forestry dropped remarkable to 0.08 in 1966 from 0.15 in 1963. Accordingly, the effect of inducement of indirect output of other forestry-related sectors has decreased; this is a really natural phenomenon, as compared with an increasing input coefficient generated by the re-use of forest products by the forestry sector. 3. Induced output of forestry A. Forest products, wood in particular, are supplied to other industries as their raw materials, increasng their value added. In this connection the primary dependency rate on forestry for 1963 and 1966 was compared, i. e., an increase or decrease in each sector, from 7.71 percent in 1963 to 11.91 percent in 1966 in agriculture, 10.32 to 6.11 in fishery, 16.24 to 19.90 in mining, 0.76 to 0.70 in the manufacturing sector and 2.79 to 4.77 percent in the construction sector. Generally speaking, on the average the dependency on forestry during the period 1963-1966 increased from 5.92 percent to 8.03 percent. Accordingly, it may easily be known that the primary forestry output induced by primary and secondary industries increased from 16, 109 million won in 1963 to 48, 842 million won in 1966. B. The forest products are supplied to other industries as their raw materials. The products are processed further into higher quality products. thus indirectly increasing the value of the forest products. The ratio of the increased value added or the secondary dependency on forestry for 1963 and 1966 showed an increase or decrease, from 5.98 percent to 7.87 percent in agriculture, 9.06 to 5.74 in fishery, 13.56 to 15.81 in mining, 0.68 to 0.61 in the manufacturing sector and 2.71 to 4.54 in the construction sector. The average ratio in this connection increased from 4.69 percent to 5.60 percent. In the meantime, the secondary forestry output induced by primary and secondary industries rose from 12,779 million Wall in 1963 to 34,084 million won in 1966. C. The dependency of tertiary industries on forestry showed very minor ratios of 0.46 percent and 0.04 percent in 1963 and 1966 respectively. The forestry output induced by tertiary industry also decreased from 685 million won to 123 million won during the same period. D. Generally speaking, the ratio of dependency on forestry increased from 17.68 percent in 1963 to 24.28 percent in 1966 in primary industries, from 4.69 percent to 5.70 percent in secondary industries, while, as mentioned above, the ratio in the case of tertiary industry decreased from 0.46 to 0.04 percent during the period 1963-66. The mining industry reveals the heaviest rate of dependency on forestry with 29.80 percent in 1963 and 35.71 percent in 1966. As it result, the direct forestry income, valued at 8,172 million won in 1963, shot up to 22,724 million won in 1966. Its composition ratio lo the national income rose from 1.9 percent in 1963 to 2.3 per cent in 1966. If the induced outcome is taken into account, the total forestry production which was estimated at 37,744 million won in 1963 picked up to 105,773 million won in 1966, about 4.5 times its direct income. It is further noted that the ratio of the gross forestry product to the gross national product. rose significantly from 8.8 percent in 1963 to 10.7 percent in 1966. E. In computing the above mentioned ratio not taken into consideration were such intangible, indirect effects as the drought and flood prevention, check of soil run-off, watershed and land conservation, improvement of the people's recreational and emotional living, and maintenance and increase in the national health and sanitation. F. In conclusion, I would like to emphasize that the forestry sector exercices an important effect upon the national economy and that the effect of induced forestry output is greater than its direct income.

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The Determinants of Working Poor' Poverty-Exit Possibility : Path Dependency of Working Poor Labor Market (근로빈곤층의 빈곤탈출 결정요인 연구 : 근로빈곤노동시장의 경로제약성을 중심으로)

  • Ji, Eun-Jeong
    • Korean Journal of Social Welfare
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    • v.59 no.3
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    • pp.147-174
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    • 2007
  • This study examines how path dependency of working poor labor market segmented from the primary and the secondary labor market affects employment and quality of employment of working poor. It Further examines how path dependency makes working poor to remain in the labor market and makes it difficult for them to escape from a vicious poverty cycle. Data is based on the $3{\sim}7th$ Korea Labor and Income Panel Study(KLIPS). Markov's transition probability and discrete-time hazard analysis are used for analysis. This study finds that Korea labor market is divided into three parts; the primary labor market, the secondary labor market and the working poor labor market. The proportion of employed poor has been reduced, but the proportion of non economically-active working poor has been increased and has become the main group among the working poor. This shows that labor demand of working poor is fundamentally lacking and there are structural barriers that block working poor's employment itself. The regression analysis shows that the longer working poor labor market participation is, the lower poverty-exit rate. This is an evidence of vicious poverty cycle that the poor have little chance to exit from working poor labor market, once they step into it. Therefore, the longer their participation in poor labor market, the more likely they would move only within the closed working poor labor market. Consequently, it is necessary to fundamentally reform labor market structure and to alleviate negative perception and discrimination about the poor labor while activating labor demand.

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A Study on the Effect of Export on Induction of Import (수출이 수입유발에 미치는 효과에 관한 연구)

  • Son, Yong-Jung
    • International Commerce and Information Review
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    • v.9 no.4
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    • pp.127-139
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    • 2007
  • There are three methods to examine import structures : 1) look at import coefficient, 2) import dependency, and 3) composition ratio of imported products. Therefore, this study analyses the import structure of Korea using the three methods above and when final demand occurs on produced goods and services in each industrial section, it divides import induction coefficients that indicate size of induced import directly and indirectly into consumption, investment and export to identify the effect of export on import induction.

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Interdependencies Among Design Information in an Integrated Design Model (통합설계 모델에서의 설계 정보간의 상호 의존성)

  • 이창호;리차드쏘스;이리형
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1997.10a
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    • pp.189-196
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    • 1997
  • The development of computer integrated systems for structural design requires models to describe and organize information and activities involved in design. An entity-based integrated design model involves a number of product and process entities. Product entities and process entities describe design information and design activities, respectively. One type of relationships among entities is interaction relationships, which describe interdependencies among design information. The interaction relationships can be represented as constraints. Types of constraints include demand constraints, dependency constraints, and interaction constraints. The concepts of representing and processing demand constraints in an entity-based integrated design model are presented.

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Development of Demand Forecasting Algorithm in Smart Factory using Hybrid-Time Series Models (Hybrid 시계열 모델을 활용한 스마트 공장 내 수요예측 알고리즘 개발)

  • Kim, Myungsoo;Jeong, Jongpil
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.19 no.5
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    • pp.187-194
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    • 2019
  • Traditional demand forecasting methods are difficult to meet the needs of companies due to rapid changes in the market and the diversification of individual consumer needs. In a diversified production environment, the right demand forecast is an important factor for smooth yield management. Many of the existing predictive models commonly used in industry today are limited in function by little. The proposed model is designed to overcome these limitations, taking into account the part where each model performs better individually. In this paper, variables are extracted through Gray Relational analysis suitable for dynamic process analysis, and statistically predicted data is generated that includes characteristics of historical demand data produced through ARIMA forecasts. In combination with the LSTM model, demand forecasts can then be calculated by reflecting the many factors that affect demand forecast through an architecture that is structured to avoid the long-term dependency problems that the neural network model has.

A Partition Technique of UML-based Software Models for Multi-Processor Embedded Systems (멀티프로세서용 임베디드 시스템을 위한 UML 기반 소프트웨어 모델의 분할 기법)

  • Kim, Jong-Phil;Hong, Jang-Eui
    • The KIPS Transactions:PartD
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    • v.15D no.1
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    • pp.87-98
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    • 2008
  • In company with the demand of powerful processing units for embedded systems, the method to develop embedded software is also required to support the demand in new approach. In order to improve the resource utilization and system performance, software modeling techniques have to consider the features of hardware architecture. This paper proposes a partitioning technique of UML-based software models, which focus the generation of the allocatable software components into multiprocessor architecture. Our partitioning technique, at first, transforms UML models to CBCFGs(Constraint-Based Control Flow Graphs), and then slices the CBCFGs with consideration of parallelism and data dependency. We believe that our proposition gives practical applicability in the areas of platform specific modeling and performance estimation in model-driven embedded software development.