An Exact Solution Approach for Release Planning of Software Product Lines

Jaewook Yoo 한국산업경영시스템학회 2012 한국산업경영시스템학회 학술대회 Vol.2012 No.춘계

Software release planning in software development is to assign its features to releases in a specified planning horizon,satisfying technology, resource, risk, and budget constraints. The release planning problembecomes more complicated when the concept of software product lines (SPL) is considered. In this research, a precedence-constrained multiple 0-1 knapsack problem regarding SPL characteristics is formulated to maximize the objective function depending on the value of the release, the importance of stakeholders, the urgency of a feature and its value to stakeholders. As the optimization solution approach, dynamic programming model is developed to solve the precedence-constrained multiple 0-1 knapsack problem as well as a heuristic and reduction algorithm are applied to reduce the size of the problem at each stage

다수의 개별시장 하에서 QFD의 기술속성의 최적 값을 결정하기 위한 동적 계획법

Jaewook Yoo 한국산업경영시스템학회 2015 한국산업경영시스템학회지 Vol.38 No.2

Quality function deployment (QFD) is a useful method in product design and development to maximize customer satisfaction. In the QFD, the technical attributes (TAs) affecting the product performance are identified, and product performance is improved to optimize customer requirements (CRs). For product development, determining the optimal levels of TAs is crucial during QFD optimization. Many optimization methods have been proposed to obtain the optimal levels of TAs in QFD. In these studies, the levels of TAs are assumed to be continuous while they are often taken as discrete in real world application. Another assumption in QFD optimization is that the requirements of the heterogeneous customers can be generalized and hence only one house of quality (HoQ) is used to connect with CRs. However, customers often have various requirements and preferences on a product. Therefore, a product market can be partitioned into several market segments, each of which contains a number of customers with homogeneous preferences. To overcome these problems, this paper proposes an optimization approach to find the optimal set of TAs under multi-segment market. Dynamic Programming (DP) methodology is developed to maximize the overall customer satisfaction for the market considering the weights of importance of different segments. Finally, a case study is provided for illustrating the proposed optimization approach.

QFD 최적화에서 퍼지 넘버의 이용

Jaewook Yoo 한국산업경영시스템학회 2016 한국산업경영시스템학회지 Vol.39 No.2

Quality function deployment (QFD) is a widely adopted customer-oriented product development methodology by translating customer requirements (CRs) into technical attributes (TAs), and subsequently into parts characteristics, process plans, and manufacturing operations. A main activity in QFD planning process is the determination of the target levels of TAs of a product so as to achieve a high level of customer satisfaction using the data or information included in the houses of quality (HoQ). Gathering the information or data for a HoQ may involve various inputs in the form of linguistic data which are inherently vague, or human perception, judgement and evaluation for the information and data. This research focuses on how to deal with this kind of impreciseness in QFD optimization. In this paper, it is assumed as more realistic situation that the values of TAs are taken as discrete, which means each TA has a few alternatives, as well as the customer satisfaction level acquired by each alternative of TAs and related cost are determined based on subjective or imprecise information and/or data. To handle these imprecise information and/or data, an approach using some basic definitions of fuzzy sets and the signed distance method for ranking fuzzy numbers is proposed. An example of a washing machine under two-segment market is provided for illustrating the proposed approach, and in this example, the difference between the optimal solution from the fuzzy model and that from the crisp model is compared as well as the advantage of using the fuzzy model is drawn.

A Genetic Algorithm for Solving a QFD(Quality Function Deployment) Optimization Problem

Jaewook Yoo 한국콘텐츠학회 2020 International Journal of Contents Vol.16 No.4

CREATING AND SHARING A BIGGER VALUE -DUAL PROCESS MODEL OF INTER-FIRM CSV TO FIRM PERFORMANCE

Hyeonmi Yoo,JaeWook Kim 글로벌지식마케팅경영학회 2016 Global Marketing Conference Vol.2016 No.7

아웃소싱 전략을 활용하는 두 단계 흐름생산라인에서 완료시간의 총합을 최소화하는 일정계획문제

유재욱(Jaewook Yoo),이익선(Ik Sun Lee) 한국경영과학회 2016 經營 科學 Vol.33 No.2

We treats a job scheduling in a 2-machine flow-shop problem with outsourcing strategy allowed. Jobs in the first machine are processed in-house or outsourced to the other companies. In this paper, all the considered jobs are determined to be in-house processed or outsourced. When a job is outsourced, then the firm should pay an outsourcing cost additionally. We want to minimize the sum of the outsourcing costs and the total completion times of finished jobs. In this paper, some solution properties are characterized, and then some heuristic algorithms and a branch-and-bound solution algorithm are derived. This paper evaluates finally the performance of the proposed algorithms during the numerical tests.

아웃소싱을 고려한 제품군설계에 관한 최적화 연구

유재욱(Jaewook Yoo),양재영(Jae Young Yang) 한국경영과학회 2019 經營 科學 Vol.36 No.1

A make-or-buy (MOB) decision about some technical attributes in product design and development is the act of choosing between making them in-house or purchasing from an external supplier. In this study, the transaction cost approach is used to reflect the MOB decision to the product line design optimization problem. The problem including the MOB decision is formulated as a multi-objective function model to satisfy three aspects of interest in product design and development as well as a column-dropping rule is proposed as the solution approach. The proposed model and solution approach are illustrated with a tablet pc under multi-segment market, and the sensitivity analysis is performed to study how the proposed model and its solutions respond to the variation for the priority of the objective functions.

마코프 프로세스와 역대 판매량 실적을 이용한 IT 제품 수명주기 예측 모델링에 관한 연구 -아이폰 사례-

유재욱(Jaewook Yoo) 한국산학기술학회 2021 한국산학기술학회논문지 Vol.22 No.10

오늘날 시장 환경에서 IT 제품의 수명주기는 매우 짧을 뿐만 아니라 한 기업이 개발한 두개 또는 세 개 세대 이상의 제품들이 출시 시점은 다르더라도 같은 시장 세그먼트에서 상당 기간 동안 겹쳐서 시장에 상존하는 상황이 빈번히 발생하고 있다. 본 연구에서는 이와 같이 제품수명주기가 짧고 한 기업이 여러 세대 제품군을 한 시장에 출시하는 시장 환경에서 마코프 프로세스를 이용한 제품수명주기를 예측하는 모델을 제시한다. 본 연구에서 제시한 모델을 실제 사례에 적용하기 위하여 애플의 과거 2007년 3분기부터 2018년 3분기까지 총 45개 분기의 14개 세대 아이폰들의 분기별 글로벌 판매량 데이터 수집하였고 본 연구의 모델이 제대로 적용되도록 세대제품별 판매량 데이터를 추정하였다. 본 연구의 모델의 타당성을 검증하기 위해서 10개의 테스트가 수행되었다. 모델의 성능을 보여주기 위하여 본 연구의 모델이 주는 제품수명주기 상태의 기대값과 실제값인 관측값의 차이를 관측값에 대한 백분율로 측정하였다. 아이폰 사례의 경우 본 연구가 제시한 마코프 프로세스를 이용한 제품수명주기 예측모델은 미래 아이폰의 제품수명주기 상태를 예측하는 성능이 94.28% 였다. In this study, we present a Markov model to predict the product life cycle in today"s market environment where the product life cycle is short, and a company releases multiple generation products in one market. To apply the model presented in this study to an actual case, we collected quarterly global sales data of 14 generations of iPhones. The data were collected from 45 quarters of Apple from the 3rd quarter of 2007 to the 3rd quarter of 2018 . The sales data of each generation product were estimated for proper application. Ten tests were conducted to verify the validity of the model. To demonstrate the model"s performance, we measure the difference between the expected value of the product life cycle state obtained by the model of this work and the actual value of the observation as a percentage of the observed value. In the case of the iPhone, the product life cycle prediction Markov model proposed by this study showed 94.28% performance in predicting the iPhone"s future product life cycle status.

중앙창고 입지선정을 위한 회귀분석기반 해법

유재욱(Jaewook Yoo),이동주(Dongju Lee) 한국산업경영시스템학회 2009 한국산업경영시스템학회지 Vol.32 No.2

In continuous review inventory model, (Q, r) system, order quantity(Q) and reorder point(r) should be determined to calculate inventory-related cost that consists of setup, holding, and penalty costs. The procedure to obtain the exact value of Q and r is complex. In this paper, a regression analysis is proposed to get the approximate inventory-related cost without the determination of Q and r in the case that the standard deviation(σ) of the lead time demand is small or that the mean(μ) of the lead time demand is proportional to σ. To save inventory-related cost, central warehouses with (Q, r) system can be built. Central warehouse can provide some stores with products with the consideration of the tradeoff between inventory-related cost and transportation cost. The number and the location of central warehouses to cover all the stores are determined by a regression-based approach. The performance of the proposed approach is tested by using some computational experiments.

경쟁행위 요인과 기업성과 간의 관계에 대한 실증적 연구

유재욱(Jaewook Yoo) 한국인터넷전자상거래학회 2011 인터넷전자상거래연구 Vol.11 No.1

This study examines the relationships between competitive-behaviors attribute and firm performance in Korean life-insurance industry. The findings of a multiple regression analysis of ten-years sample of life-insurance companies in Korea represent that the action frequency has significant positive relations with new business rate whereas the response frequency of them has significant positive relations with persistent business rate. Inconsistent with the hypotheses, however both action- and response-speed did not reveal the positive relations with either of quantity or quality of firms performance. The present study contributes to an under-researched, yet very important area in competitive dynamics. In particular, the findings of this study imply that future study in competitive dynamics should adopt a dynamic approach than static approach in an empirical analysis. They are also valuable to practicing managers in life-insurance firms in Korea by adding their understanding of the ongoing competitive dynamics in the market.