Massively Multiplayer Online Role-Playing Game(MMORPG) attract thousand of concurrent users, leading to a surge in server requests. The massive requests results in contention on the game server, causing unexpected latency issues that undermine user experience. Delayed latency leads to user dissatisfaction and, ultimately, user churn. In this paper, we propose a multi-threaded game server design that provides stable response time by utilizing computing resources. And we study the performance of the design under various environments by configuring the approaches we implemented. The server consists of a socket system that helps communicate between clients and servers, a task system that handles changes in the status of user, and a synchronization system that allows users to receive the same game information. To prevent serious contention, both lock and lock-free algorithms for process synchronization are applied, and some parallel programming approaches such as visual processing are introduced.
디지털 트랜스포메이션은 기업의 경영 전략적 관점에서의 조직, 프로세스, 비즈 니스 모델, 커뮤니케이션의 광범위하고 근본적 변화를 요구하고 있으나, 성공적인 트랜스포 메이션의 핵심 선제요건 중 하나는 구성원의 IT(Information Technology) 역량이다. 공학적 배경 지식 없이 기술경영을 전공하는 학생들은 비교적 단기간에 경영관리 능력과 IT 역량을 동시에 키워야 하는 난제에 처해 있다. 이러한 이유로 효과적인 IT 역량 교육 방법은 기술경 영학 분야의 교육 이슈 중 하나로 부각되고 있다. 본 논문은 디지털 트랜스포메이션의 흐름을 주도할 수 있는 학생들을 양성하기 위한 IT 역량 교육은 “무엇”을 “어떻게” 가르쳐야 할 것 인가라는 질문에 대한 답을 찾기 위한 하나의 사례로서, 서강대학교 기술경영 전문대학원의 IT 관련 커리큘럼 리노베이션의 과정과 현재까지 교육과정 실행 결과를 제시한다. 특히, IT 역량 교육의 출발점이자 진입장벽이 되는 기초 프로그래밍 교육 과정의 피드백 결과에 대한 충분한 논의를 통해, 기술경영대학원 학생들을 위한 효율적인 IT 교육의 운영 방향에 대한 선행 참조사례를 제공하는 데 본 논문의 목적이 있다.
The purpose of this study is to analyze information about dietary information presented in the television broadcast media in order to determine the optimal communication method that will provide desirable information to the general public. To that end, stakeholders were recruited and trained before and during the study. Three airwaves broadcasters and four comprehensive programming channels were monitored for Three months. The results are as follows. In total 172 food and nutrition programs are reported on. As information from the monitored programs was investigated, results showed a frequency of 136 separate informative programs (79.1%) and 36 entertainment programs (20.9%). Second, the broadcasters included are KBS, MBC, SBS, while the channels are TV Chosun, JTBC, Channel A, and MBN. Third, 109 reports (63.3%) were about ingredients & cuisine, followed by 63 reports (36.7%) on health and diet. This research provides transitional knowledge regarding the correlation between dietary information and the media. Moreover, this research contributes to advocating public health by enhancing the quality from broadcast media about dietary information.
ICT 산업의 글로벌 시장을 선점할 수 있는 다음 세대의 개발이 필요한 상황이 일어남에 따라 웨어러블 디바이스 의 생체 신호 모니터링에 대한 관심이 크게 증가하고 있다. 이에 따라 본 연구에서는 히스테리시스가 적은 E-Band를 사용하여 단일벽 탄소나노튜브(SWCNT) 분산 용액에 함침 공정을 통해서 저항형 직물 인장 센서(Resistive textile strain sensor)를 개발하였다. 전기전도성이 부여된 e-band에 저항 신호를 측정하기 위해 만능재료시험기(UTM)과 Microcontroller unit인 아두이노와 LCR 미터를 이용해서 인장의 변화에 따른 저항 변화를 측정하였다. 원단으로 이 루어진 텍스타일 스트레인 센서의 특성상 발생하는 다양한 노이즈들을 효과적으로 처리하기 위하여 신호처리 과정 (Signal processing)의 노이즈 필터링의 이동평균 필터, 사비츠키-골레이 필터, 중앙값 필터들을 사용하여 센서의 필 터 성능을 평가하였다. 그 결과 이동평균 필터의 필터링 결과의 신뢰도가 최소 89.82%, 최대 97.87%으로 이동평균 필터링이 텍스타일 스트레인 센서의 노이즈 필터링 방식으로 적합하였다.
The topic of this study is the field of humanitarian logistics for disaster response. Many existing studies have revealed that compliance with the golden time in response to a disaster determines the success or failure of relief activities, and logistics costs account for 80% of the disaster response cost. Besides, the agility, responsiveness, and effectiveness of the humanitarian logistics system are emphasized in consideration of the disaster situation’s characteristics, such as the urgency of life-saving and rapid environmental changes. In other words, they emphasize the importance of logistics activities in disaster response, which includes the effective and efficient distribution of relief supplies. This study proposes a mathematical model for establishing a transport plan to distribute relief supplies in a disaster situation. To determine vehicles’ route and the amount of relief for cities suffering a disaster, it mainly considers the urgency, effectiveness (restoration rate), and uncertainty in the logistics system. The model is initially developed as a mixed-integer nonlinear programming (MINLP) model containing some nonlinear functions and transform into a Mixed-integer linear programming (MILP) model using a logarithmic transformation and piecewise linear approximation method. Furthermore, a minimax problem is suggested to search for breakpoints and slopes to define a piecewise linear function that minimizes the linear approximation error. A numerical experiment is performed to verify the MILP model, and linear approximation error is also analyzed in the experiment.
PURPOSES: Pavement Management System contains the data that describe the condition of the road. Under limited budget, the data can be utilized for efficient plans. The objective of this research is to develop a mixed integer program model that maximizes remaining durable years (or Lane-Kilometer-Years) in road maintenance planning.
METHODS: An optimization model based on a mixed integer program is developed. The model selects a cluster of sectors that are adjacent to each other according to the road condition. The model also considers constraints required by the Seoul Metropolitan Facilities Management Corporation. They select two lanes at most not to block the traffic and limit the number of sectors for one-time construction to finish the work in given time. We incorporate variable cost constraints. As the model selects more sectors, the unit cost of the construction becomes smaller. The optimal choice of the number of sectors is implemented using piecewise linear constraints.
RESULTS: Data (SPI) collected from Pavement Management System managed by Seoul Metropolitan City are fed into the model. Based on the data and the model, the optimal maintenance plans are established. Some of the optimal plans cannot be generated directly in existing heuristic approach or by human intuition.
CONCLUSIONS: The mathematical model using actual data generates the optimal maintenance plans.
In recent years, business environment is faced with multi uncertainty that have not been suffered in the past. As supply chain is getting expanded and longer, the flow of information, material and production is also being complicated. It is well known that development service industry using application software has various uncertainty in random events such as supply and demand fluctuation of developer’s capcity, project effective date after winning a contract, manpower cost (or revenue), subcontract cost (or purchase), and overrun due to developer’s skill-level. This study intends to social contribution through attempts to optimize enterprise’s goal by supply chain management platform to balance demand and supply and stochastic programming which is basically applied in order to solve uncertainty considering economical and operational risk at solution supplier. In Particular, this study emphasizes to determine allocation of internal and external manpower of developers using S&OP (Sales & Operations Planning) as monthly resource input has constraint on resource’s capability that shared in industry or task. This study is to verify how Stochastic Programming such as Markowitz’s MV (Mean Variance) model or 2-Stage Recourse Model is flexible and efficient than Deterministic Programming in software enterprise field by experiment with process and data from service industry which is manufacturing software and performing projects. In addition, this study is also to analysis how profit and labor input plan according to scope of uncertainty is changed based on Pareto Optimal, then lastly it is to enumerate limitation of the study extracted drawback which can be happened in real business environment and to contribute direction in future research considering another applicable methodology.
We analyzed information provided by diet-related programs of comprehensive programming channels and the relationship between composition of professional panelists and quality of provided information. We selected 82 items among eight programs by MBN, JTBC, and TV chosun. All 82 items provided information about food & nutrition and health & disease, but only 32 items (39.0%) and 35 items (42.7%) provided information on food culture and food safety, respectively. Among the food ingredients, phytochemicals (81.7%) were the most frequently mentioned, and the contents of functional ingredients occupied a large part. The inappropriate information on programs were broadcast on an average of 1.2 episodes per program, and the most pointed out item was information that could confuse viewers with drugs (29.3%). Among the professional panelists, medical doctors (38.9%) and Oriental medicine doctors (16.6%) had the highest number of appearances, and professors of food & nutrition constituted only 7.1%. However, the increase in the number of appearances of professors showed a positive effect on the quality of program information. Contents focused on balanced nutrient intake and dietary culture of Korea should be increased rather than focusing on the function of each nutrient in comprehensive programming channels.
This study focuses on the formation of input release lots in a semiconductor wafer fabrication facility. After the order-lot pegging process assigns lots in the fab to orders and calculates the required quantity of wafers for each product type to meet customers’ orders, the decisions on the formation of input release lots should be made to minimize the production costs of the release lots. Since the number of lots being processed in the wafer fab directly is related to the productivity of the wafer fab, the input lot formation is crucial process to reduce the production costs as well as to improve the efficiency of the wafer fab. Here, the input lot formation occurs before every shift begins in the semiconductor wafer fab. When input quantities (of wafers) for product types are given from results of the order-lot pegging process, lots to be released into the wafer fab should be formed satisfying the lot size requirements. Here, the production cost of a homogeneous lot of the same type of product is less than that of a heterogeneous lot that will be split into the number of lots according to their product types after passing the branch point during the wafer fabrication process. Also, more production cost occurs if a lot becomes more heterogeneous. We developed a multi-dimensional dynamic programming algorithm for the input lot formation problem and showed how to apply the algorithm to solve the problem optimally with an example problem instance. It is necessary to reduce the number of states at each stage in the DP algorithm for practical use. Also, we can apply the proposed DP algorithm together with lot release rules such as CONWIP and UNIFORM.
This study aimed to evaluate the effectiveness of closed season policy using an integer linear programming, targeting the large purse seine fishery in Korea. In the analysis, based on Cheng and Townsend(1993), fishing effort (fishing days by month) was assumed to be distributed for profit maximization of vessels and catch of immature fish was estimated. The analytical results showed that the effects of closed season policy would vary in accordance with the monthly closures in terms of fishing profits and catch of immature fish. A closed season policy by month had different effects on fishing profits and catch of immature fish by species. It implies the importance of considering seasonal changes of fish species when limiting fishing efforts with the closed season policy.
In this paper, we present a multi-period 0-1 knapsack problem which has the cardinality constraints. Theoretically, the presented problem can be regarded as an extension of the multi-period 0-1 knapsack problem. In the multi-period 0-1 knapsack problem, there are n jobs to be performed during m periods. Each job has the execution time and its completion gives profit. All the n jobs are partitioned into m periods, and the jobs belong to i-th period may be performed not later than in the i-th period, i = 1, ⋯, m. The total production time for periods from 1 to i is given by bi for each i = 1, ⋯, m, and the objective is to maximize the total profit. In the extended problem, we can select a specified number of jobs from each of periods associated with the corresponding cardinality constraints. As the extended problem is NP-hard, the branch and bound method is preferable to solve it, and therefore it is important to have efficient procedures for solving its linear programming relaxed problem. So we intensively explore the LP relaxed problem and suggest a polynomial time algorithm. We first decompose the LP relaxed problem into m subproblems associated with each cardinality constraints. Then we identify some new properties based on the parametric analysis. Finally by exploiting the special structure of the LP relaxed problem, we develop an efficient algorithm for the LP relaxed problem. The developed algorithm has a worst case computational complexity of order max[O(n2log n), O(mn2)], where m is the number of periods and n is the total number of jobs. We illustrate a numerical example.
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.
This study aimed to empirically investigate the applicability of ecosystem-based TAC (Total Allowable Catch) fisheries management targeting the large purse seine fishery where multi-species are regulated by TAC. Using a linear programming, the optimal fishing effort and the catch amount by species which maximize fishing profits were analyzed under the constraint condition of catch limits by species. Analytical results showed that an application of TAC on only chub mackerel would have negative impacts on fish stocks such as hairtail and jack mackerel by increasing the level of fishing effort to achieve its allocated catch limit. However, under the constraint condition of catch limits of all species, it was shown that optimal catches of all species were achieved within their catch limits. It implies the importance of ecosystem-based management considering biological and technical interactions of species those were excluded in the traditional single species fisheries management.
이 연구는 다문화교육 학습 프로그램을 개발하여 글로벌사회에 필요한 민주시민의식 함양을 위한 것으로 연구자의 담임학급 중학교 2학년 1반 37명을 대상으로 연구 되었다. 학습주제에 따라 차시별 연간 학습지도안을 구성하여 다문화교육 학습프로그램을 개발 적용한 결과, 다른 나라의 가치관과 생활 방식을 이해하고 수용하는 마음과 국제 사회와 외국인에 대해 합리적인 태도를 가졌으며 지구촌의 문제 해결을 위해 노력하고 있는 단체에 대한 관심도 가지게 되었다. 연구 결과 다문화교육 프로그램의 지속적인 운영으로 평등한 입장에서 다른 나라 문화를 존중할 줄 알고 수용하는 자세를 갖는 민주시민의식 함양에 효과적인 결과가 있음을 알 수 있었다.
Control allocation is an important part of a system. It implements the function that map the desired command forces from the controller into the commands of the different actuators. In this paper, the authors present an approach for solving constrained control allocation problem in vessel system by using multi-parametric quadratic programming (mp-QP) algorithm. The goal of mp-QP algorithm applied in this study is to compute a solution to minimize a quadratic performance index subject to linear equality and inequality constraints. The solution can be pre-computed off-line in the explicit form of a piecewise linear (PWL) function of the generalized forces and constrains. The efficiency of mp-QP approach is evaluated through a dynamic positioning simulation for a vessel by using four tugboats with constraints about limited pushing forces and found to work well.
이 논문은 병렬 설비로 이루어진 다수의 단계를 포함하는 재방문이 있는 혼합흐름공정의 계획 문제를 다룬다. 재방문작업에서 제품은 몇몇 공정을 여러 번 방문하게 되고 이로 인하여 재공의 혼잡과 장비의 유휴의 원인이 된다. 이 상황에서는 생산성과 고객 만족도를 향상 시키는 것이 중요한 이슈이다. 따라서 본 논문은 혼합흐름공정에서 스루풋을 최대화하고 지연된 고객 수요를 최소화하기 위해 우선순위 목표계획법 기반의 휴리스틱 방법들을 제안한다. 그리고 이 휴리스틱