• Journal of Digital Convergence
• /
• v.11 no.11
• /
• pp.209-217
• /
• 2013

This study focuses on the analysis of purchased items' relationship occurred by consumers' purchasing behavior observed in on-line shopping mall based on social network analysis. In order to find relational characteristics of each item for establishing marketing strategy, we apply three definitions of centrality in network, which are degree centrality, betweenness centrality, and closeness centrality in the purchased items' network. Thus, the research results provide the criteria for selection of market segmentation variables. Furthermore, the details of case has been introduced to validate the analyzed results in terms of marketing strategy, and supporting evidences are provided accordingly.

• Journal of The Korean Astronomical Society
• /
• v.52 no.4
• /
• pp.109-119
• /
• 2019

While the reverberation mapping technique is the best available method for measuring black hole mass in active galactic nuclei (AGNs) beyond the local volume, this method has been mainly applied to relatively low-to-moderate luminosity AGNs at low redshift. We present the strategy of the Seoul National University AGN Monitoring Project, which aims at measuring the time delay of the $H{\beta}$ line emission with respect to AGN continuum, using a sample of relatively high luminosity AGNs out to redshift z ~ 0.5. We present simulated cross correlation results based on a number of mock light curves, in order to optimally determine monitoring duration and cadence. We describe our campaign strategy based on the simulation results and the availability of observing facilities. We present the sample selection, and the properties of the selected 100 AGNs, including the optical luminosity, expected time lag, black hole mass, and Eddington ratio.

• Journal of dental hygiene science
• /
• v.21 no.1
• /
• pp.63-69
• /
• 2021

Background: This study aimed to identify the role of dental hygienists in exchanges between North and South Korea to lower gaps in the level of dental healthcare between the two countries by conducting a Delphi survey with specialists and identifying alternative policies regarding the utilization of dental hygienists in such exchanges. Methods: Two Delphi surveys were conducted with the participation of nine specialists, and descriptive statistical analyses including mean and standard deviation were performed on the collected data. Results: Among methods of exchange and cooperation regarding oral healthcare under the current North Korean medical system, the issue considered most urgent was the "establishment of oral healthcare infrastructure." The most important short-term strategy was identified as the "selection and formation of partnerships in the field of inter-Korean oral health exchange and cooperation." The mid-term strategy was identified as the "establishment of cooperation in the dental industry, centered on educational cooperation projects." The long-term strategy included "joint R&D projects, oral health surveys, and business development." In order to determine how best to use dental hygienists during inter-Korean exchanges and cooperation, the respondents placed urgency on the "establishment of joint cooperation projects for oral health promotion and early examination and the treatment of dental diseases and planning of community research projects" and "the role of oral health education and media development for residents." Conclusion: Cooperation is necessary regarding the preparation of oral healthcare exchanges that aim to encourage unity between North and South Korea and reduce the gaps between the North and South regarding oral health conditions. Therefore, continuous and reasonable discussions and research are needed regarding the utilization of dental hygienists in such exchanges.

• Smart Media Journal
• /
• v.10 no.3
• /
• pp.39-47
• /
• 2021

Enhanced index tracking is a problem of optimizing the objective function to generate returns above the index based on the index tracking that follows the market return. In order to avoid problems such as large transaction costs and illiquidity, we used a method of constructing a portfolio by selecting only some of the stocks included in the index. Commonly used enhanced index tracking methods tried to find the optimal portfolio with only one objective function in all tested periods, but it is almost impossible to find the ultimate strategy that always works well in the volatile financial market. In addition, it is important to improve generalization performance beyond optimizing the objective function for training data due to the nature of the financial market, where statistical characteristics change significantly over time, but existing methods have a limitation in that there is no direct discussion for this. In order to solve these problems, this paper proposes ensemble learning that composes a portfolio by combining several objective functions and a 3-stage portfolio selection algorithm that can select a portfolio by applying criteria other than the objective function to the training data. The proposed method in an experiment using the S&P500 index shows Sharpe ratio that is 27% higher than the index and the existing methods, showing that the 3-stage portfolio selection algorithm and ensemble learning are effective in selecting an enhanced index portfolio.

• Journal of the Korea Convergence Society
• /
• v.12 no.5
• /
• pp.267-274
• /
• 2021

This study was designed to investigate the variables affecting Chinese university students' selection factors for Korean drama. Participants in this study were 379 university students from Hunan Province, China. An online survey program(www.wjx.cn) was used to collect data for this study. The tool of this study was 'a tool for measuring the selection factors of Korean Dramas', and it was composed of two areas: completeness of work and recognition. The results of this study are as follows: First, the completeness of work factor are higher than the recognition of Korean dramas by Chinese university students. Second, there are differences in the factors for selection Korean dramas according to the gender, grade, age, major, and Korean Drama watching frequency of Chinese university students. Third, when Chinese university students select Korean Dramas, their preferred genre influences the selection factors for the level of work completion and recognition. Finally, it was discussed according to the results of this study, and suggested for the qualitative re-leap of Korean Dramas in the global era. In order to expand the Korean Wave market in China, cultural contents must be developed to embrace the sentiment of Chinese university students, a propagation strategy that reflects the latest consumption trends of Chinese youth must be established, and the sophisticated visual beauty of Korean Dramas must be realized.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.8 no.2
• /
• pp.326-354
• /
• 2014

In this paper, a new green clustering algorithm is proposed to be as a first approach in the framework of an energy efficient strategy for centralized enterprise high-density WLANs. Traditionally, in order to maintain the network coverage, all the APs within the WLAN have to be powered-on. Nevertheless, the new algorithm can power-off a large proportion of APs while the coverage is maintained as its always-on counterpart. The two main components of the new approach are the faster procedure based on K-means and the more accurate procedure based on Evolutionary Algorithm (EA), respectively. The two procedures are processes in parallel for different designed requirements and there is information interaction in between. In order to implement the new algorithm, EA is applied to handle the optimization of multiple objectives. Moreover, we adapt the method for selection and recombination, and then introduce a new operator for mutation. This paper also presents simulations in scenarios modeled with ray-tracing method and FDTD technique, and the results show that about 67% to 90% of energy consumption can be saved while it is able to maintain the original network coverage during periods when few users are online or the traffic load is low.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.6 no.3
• /
• pp.211-219
• /
• 2010

This paper designs the dynamic symbol automatic trading system in Korean option market. This system is based on Multichart program which is convenient and efficient system trading tool. But the Multichart has an important restriction which has only one constant symbol per chart. This restriction causes very useful strategies impossible. The proposed design uses global variables, signal chart selection and position order exchange. So an automatic trading system with dynamic symbol works on Multichart program. To verify the proposed system, BS(Buythensell)-SB(Sellthenbuy) strategies are tested which uses the change of open-interest of stock index futures within a day. These strategies buy both call and put option in ATM at start candle and liquidate all at 12 o'clock and then sell both call and put option in ATM at 12 o'clock and also liquidate all at 14:40. From 23 March 2009 to 31 May 2010, 301-trading days, is adopted for experiment. As a result, the average daily profit rate of this simple strategies riches 1.09%. This profit rate is up to eight times of commision price which is 0.15 % per option trade. If the method which raises the profitable rate of wining trade or lower commission than 0.15% is found, these strategies make fascinated lossless trading system which is based on the proposed dynamic symbol automatic trading system.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.7 no.4
• /
• pp.651-669
• /
• 2013

In this paper, we study a novel routing algorithm based on load balancing for multi-channel wireless mesh networks. In order to increase the network capacity and reduce the interference of transmission streams and the communication delay, on the basis of weighted cumulative expected transmission time (WCETT) routing metric this paper proposes an improved routing metric based on load balancing and channel interference (LBI_WCETT), which considers the channel interference, channel diversity, link load and the latency brought by channel switching. Meanwhile, in order to utilize the multi-channel strategy efficiently in wireless mesh networks, a new channel allocation algorithm is proposed. This channel allocation algorithm utilizes the conflict graph model and considers the initial link load estimation and the potential interference of the link to assign a channel for each link in the wireless mesh network. It also utilizes the channel utilization percentage of the virtual link in its interference range as the channel selection standard. Simulation results show that the LBI_WCETT routing metric can help increase the network capacity effectively, reduce the average end to end delay, and improve the network performance.

• Culinary science and hospitality research
• /
• v.13 no.2
• /
• pp.275-291
• /
• 2007

The growth of foodservice industry has caused keen competition in the family restaurant industry. For a differentiation strategy to be competitive, on the preferential basis, it is necessary for each family restaurant business to analyze its position in the market. Therefore, this study is to certify customers' perceived servicescape and image similarity and analyzes positioning of seven family restaurants. For this research, multidimensional scaling(MDS) is performed to determine how they are positioned relative to competitors. According to the result of the positioning map(ALSCAL and PROFIT map), it is found that Outback steakhouse, T.G.I. Friday's, Bennigans' have more strong competitiveness than VIPS, Marche and Sizzler in servicescape factors and restaurant selection attribute except menu diversity. But the preference order does not follow the order of competitiveness. This result from the positioning map means that each business needs various marketing strategies that cannot be copied easily.

• Journal of Intelligence and Information Systems
• /
• v.9 no.3
• /
• pp.1-21
• /
• 2003

In this research, we developed a Multi-Agent based Negotiation Support System to be able to increase the competitive power of a company in dynamic environment and correspond to various orders of customers by diffusion of electronic commerce. The system uses the agent technology that is being embossed as new paradigm in dynamic environment and flexible system framework. The multi-agent technology is used to solve these problems through cooperation of agent. The system consists of six sub agents: Mediator, manufacturability Analysis Agent, Process Planning Agent, Scheduling Agent, Selection Agent, Negotiation-strategy Building Agent. In this paper, the proposed Multi-Agent based Negotiation Support System takes aim at the automation of transaction process from ordering to manufacturing plan through the automation of negotiation that is the most important in order-taking transaction.