• Journal of the Korean Operations Research and Management Science Society
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• v.41 no.2
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• pp.129-139
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• 2016

This paper presented a robust ship scheduling model using the quadratic programming problem. Given a set of available carriers under control and a set of cargoes to be transported from origin to destination, a robust ship scheduling that can minimize the mean-variance objective function with the required level of profit can be modeled. Computational experiments concerning relevant maritime transportation problems are performed on randomly generated configurations of tanker scheduling in bulk trade. In the first stage, the optimal transportation problem to achieve maximum revenue is solved through the traditional set-packing model that includes all feasible schedules for each carrier. In the second stage, the robust ship scheduling problem is formulated as mentioned in the quadratic programming. Single index model is used to efficiently calculate the variance-covariance matrix of objective function. Significant results are reported to validate that the proposed model can be utilized in the decision problem of ship scheduling after considering robustness and the required level of profit.

• Environmental and Resource Economics Review
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• v.9 no.2
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• pp.349-371
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• 2000

Data Envelopment Analysis model is a linear programming based technique for measuring the relative performance of organizational units where the presence of multiple inputs and outputs makes comparison difficult. A common measure for relative efficiency is weighted sum of outputs divided by weighted sum of inputs. DEA model allows each unit to adopt a set of weight that shows it in the most favorable light in comparison to the other unit. In this paper, we present the mathematical background and characteristics of DEA model, and give a short case study where we apply the DEA model to evaluate the relative efficiencies of 51 global electricity companies. The technical efficiency and scale efficiency are also to be investigated. Generating capacity and the number of employees are used for input data, and revenue, net profit and electricity sales are used for output data. We find that the companies with 100% relative efficiency are only 9 among 51 electricity companies. And the technical and scale efficiency of KEPCO is 98.7% and 78.89%, respectively. This means that the inefficiency of KEPCO is caused by the scale inefficiency. The analysis shows that the employees should be decreased by 15% at minimum to get the 100% efficiency. The result suggests that KEPCO needs the structural reform to improve the efficiency.

• ETRI Journal
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• v.36 no.6
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• pp.1041-1050
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• 2014

As the Internet Protocol TV (IPTV) service enters the broadcasting market, the competition intensifies. This paper explains the factors influencing new media subscription and their influential differences on IPTV and digital cable TV (DCTV). We use the information systems success model and gratification opportunity theory to develop our research model. We sample 621 people and collect their responses through web-based measuring software. Structural model analysis shows that the willingness to subscribe to a new broadcasting medium is influenced by three characteristics of the medium: media richness, interactivity, and video quality. Multigroup analysis reveals that motivation to use a medium partially differs between IPTV and DCTV. This research concludes that the IPTV service is not attractive enough to act as a substitute for the already existing DCTV. In addition, for the IPTV service to proliferate, its business model should be promoted with new and differentiated revenue structures and services. The managerial implications in this study help new media businesses set business goals and product functionality, and allocate resources for the continued diffusion of IPTV.

• Journal of Korean Institute of Industrial Engineers
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• v.39 no.4
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• pp.260-270
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• 2013

This paper proposes a strategic portfolio model for managing performance of online games. The portfolio matrix is composed of two dimensions: financial performance and non-financial performance. Financial performance is measured by the conventional measure, average revenue per user (ARPU). In terms of non-financial performance, five non-financial key performance indicators (KPIs) that have been widely used in the online game industry are utilized: RU (Register User), VU (Visiting User), TS (Time Spent), ACU (Average Current User), MCU (Maximum Current User). Data envelopment analysis (DEA) is then employed to produce a single performance measure aggregating the five KPIs. DEA is a linear programming model for measuring the relative efficiency of decision making unit (DMUs) with multiple inputs and outputs. This study employs DEA as a tool for multiple criteria decision making (MCDM), in particular, the pure output model without inputs. Combining the two types of performance produces the online game portfolio matrix with four quadrants: Dark Horse, Stop Loss, Jack Pot, Luxury Goods. A case study of 39 online games provided by company 'N' is provided. The proposed portfolio model is expected to be fruitfully used for strategic decision making of online game companies.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.30 no.3
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• pp.54-64
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• 2022

Airlines have been introducing self check-in kiosks to reduce check-in time and improve operational efficacy to increase business revenue. The domestic airlines have actively provided kiosks at airports which are expected to reduce their operating costs and enrich their passengers' travel convenience. Based on the above background, the study investigates the factors influencing intention to use the self check-in kiosks by employing the Extended Technology Acceptance Model (ETAM). The study, therefore, designed a research model by reviewing theories and studies on the relationship among information quality, innovativeness, perceived ease of use, perceived usefulness, and intention to use the kiosks. The structural equation model revealed the following. Information quality and innovativeness had a significantly positive influence on perceived ease of use and perceived usefulness; furthermore, perceived ease of use had a significantly positive influence on perceived usefulness. In addition, both perceived ease of use and perceived usefulness had a significantly positive influence on intention to use. The results indicate that the airlines should constantly develop user-friendly contents and design of the self check-in kiosks.

• Journal of Distribution Science
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• v.13 no.2
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• pp.55-62
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• 2015

Purpose - This study aims to investigate the success factors pertaining to K-POPs from an analysis of the internal business environment. Much research has investigated Korean Moves or how to popularize them. The research mainly focused on aspects of Korean Moves. However, few studies have attempted to examine Korean Moves or K-POPs from a managerial viewpoint. The current research tries to investigate the success factors of K-POP from strategic perspectives, specifically utilizing internal resource based view perspectives. It differentiates itself by looking at the competitiveness of K-POP from the internal resources. Research design, data, and methodology - In the entertainment industry, where creativity is heavily stressed, competitiveness is often regarded within the organization as a form of intangible asset, knowledge, or technology that is often related with the organization's personnel. Some research has tried to reveal the competitiveness of K-POP using Porter's competitiveness of nations framework. Others utilize the adapted model of Porter's structure. However, these models only look at the outside environment, and not inside a firm's resource, knowledge, or capabilities. This research utilizes the VRIO model to examine the internal resources and capabilities of K-POP producers. The model measures whether a firm's internal resources and capabilities are valuable, rare, difficult to imitate by competitors, or organizable. The research covered businesses whose yearly revenue exceeds $10 Million in music planning and recording in South Korea. There were only thirteen such companies (one percent of the total population). Of these, companies for whom 20 percent or more of the sales revenue comes from the abroad are targeted. Only seven are selected and these participated in the research. In order to find a firm's internal resources, we conducted qualitative research methodology. Their business names and persons who participated in this research are not revealed due to case sensitive issues. Instead, we use unrelated initials for their names and their statements. Results - From the in-depth interview with top-tier K-POP producers and managers, the current research tried to identify resources and capabilities that helped to strengthen their competitiveness. These resources and capabilities are sought from the scope of the VRIO model, which looks at the internal resources and capabilities from the scope of value, rarity, imitability, and organization. Interviews with the top tier producers and managers reveal the internal success factors of K-POPs. We conclude that these resources and capabilities are from internally accumulated producing know-how, unique managing (training) system, and outstanding all-round entertainment capabilities of the performers. Conclusions - These results indicate that the core resources and capabilities of K-POP are robust. It will take a significant amount of time and money to imitate for followers, because these resources and capabilities are the result of time investment and are embedded into producers' and performers' know-how. Taking Luo (2000)'s argument, K-POP is in the second stage of the globalization process, which is configuring and allocation resource capabilities to a global scope.

• Journal of Distribution Science
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• v.14 no.4
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• pp.47-53
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• 2016

Purpose - The objective of this study is to investigate the dynamic relationships among Advertising Cost (AD), Newly Registered Users(NRU), and Buying Users(BU) of Social Network Game(SNG). SNG is getting pervasive mainly due to the rapid growth of mobile game and Social Network Service(SNS). It would be helpful for marketing researchers interested in SNG and related practitioners to understand the changes in AD, NRU, and BU with time as well as the effects on one another in mutual and dynamic way. Research Design, Data, and Methodology - Necessary data were collected from Social Network Game(SNG) company. AD, NRU, and BU are endogenous variables, but new event such as launching (event) and holidays(holiday) are exogenous dummy variables. Vector Auto regression (VAR) model is generally used to examine and capture the dynamic relationships among endogenous variables. VAR model can easily capture dynamic and endogenous relationships among time-series variables. Vector Auto regression with Exogenous variables(VARX) is a model in which exogenous variables are added to VAR. To investigate this study, VARX is applied. Result - By estimating the VARX model, the author finds that the past periods' NRU affect negatively and significantly the present AD, and past periods' BU have a positive and significant impact on the increase of AD. In addition, the author shows that the past periods' AD and BU have a positive and significant effect on the increase of NRU, and the past periods' AD affect positively and significantly BU. While the impact of AD on NRU happens after 3 or 4 days (carryover effect), that of AD on BU comes about within just 1 or 2 days (immediate effect). The effect of BU on NRU can be considered as word of mouth (WOM effect). Therefore, SNG companies can obtain not only the growth of revenue but also the increase of NRU by increasing BU. Through those results, the author can also find that there are significant interactions between endogenous variables. Conclusion - This study intends to investigate endogenous and dynamic relationships between AD, NRU, and BU. They also give managerial implications to practitioners for SNS and SNG firms. Through this study, it is found that there exist significant interactions and dynamic relationships between those three endogenous variables. The results of this study can have meaningful implications for practitioners and researchers of SNG. This research is unique in that it deals with "actual" field data and intend to find "actual" relationships among variables unlike other related existing studies which intend to investigate psychological factors affecting the intention of game usage and the intention of purchasing game items. This study is also meaningful by showing that the increase of BU can be a good strategy for "killing birds with one stone" (i.e., revenue growth and NRU increase). Although there are some limitations related with future research topics, this research contributes to the current research on SNG marketing in the above mentioned ways.

• Analyses & Alternatives
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• v.5 no.2
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• pp.77-105
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• 2021

Natural gas consumption in Asia is growing at fast tempo because of various factors such as economic growth in the region, urbanization, coal-to-gas switch at power and industry sector. Due to geographical characteristics and lack of international pipeline connections between countries in the continent, majority of natural gas exported to Asian consumers is transported by tankers on the sea in the form of liquefied natural gas. As Asian market is the most lucrative market with the fastest demand growth, the competitions between LNG sellers for market share in Asian market are strengthening. The competitions accelerated, especially after the introduction of large volume of incremental supply into the market by new exporters from the U.S., Australia, and Russia. Cheniere Energy, the first exporter of liquefied natural gas (LNG) in the lower 48 states of U.S. has not adopted the traditional price formation mechanism and business model. Traditionally, prices of long-term LNG contracts have been indexed to the price of competing fuels, such as crude oil. The company adopted a pricing mechanism and business model based on a cost-plus system. Cheniere Energy opted for the safer and the risk-free pricing system, that annually guarantees a fixed amount of revenue to the seller. The company earns the same amount of money, regardless of natural gas price dynamics in the domestic and international market, but possibly with less revenue. However, by introducing and successfully implementing the safer and risk- free business model, Cheniere Energy, a company of a relatively smaller size in comparison with major oil and gas companies, became an example to other smaller-sized companies in the U.S. The company's business model demonstrated how to enter and operate LNG business amid increasing competitions among sellers in the U.S. and international market.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.1
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• pp.209-223
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• 2015

Google was established an online service company. Lately, Google has widened to the business area until manufacturing industry. Apple was established a computer manufacturing company. So, new business models should develop and should be innovation in order to adapt to industry environments. New business model's development and innovation are attracted on strategy to expect the high performance at companies. In particular, it is important to companies facing a variety of problems. Therefore, the purposes of this study are as follows : First, there understand the perception difference on online service company, offline service company, manufacturing company. Second, there provide for the use of strategy on online service company, offline service company, manufacturing company. The results of this study are customer factor, strategy factor, revenue factor have been statistically significant differences using ANOVA analysis in industry field, and customer factor has been statistically significant difference using t-test in business field. Then, it will expect to increase business competition through the business model.

• The Journal of Fisheries Business Administration
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• v.47 no.3
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• pp.15-33
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• 2016

This study aims to analyze effectiveness of the resource use under the total allowable catch system (TACs) of Comb pen shell, a species among TAC targeting ones through its stock assessment based on the surplus production model such as the Clark Yoshimoto Pooley (CYP) model. Particularly, this study is separated into five analysis periods in order to understand changes in Comb pen shell resource and its efficient use after TAC system implemented in 2001. The results of this study are as follows. First, five sustainable yield curves (SYCs) and exponential growth functions (EGFs) produced by the surplus production model based on Gompertz growth function to compare before and after implementation of the Korean TAC system show that the TAC system has generated a positive stock rebuilding effect for Comb pen shell caught by the diver fishery since 2001. Secondly, five profits based on differences between the sustainable total revenue (STR) and the total cost (TC) with respect to fishing efforts present that the TAC system has increased efficiency of resource use of Comb pen shell caught by the diver fishery after implementation of the Korean TAC system. In conclusion, the Korean TAC system has increased efficiency of resource use as well as has led a positive stock rebuilding effect for Comb pen shell.