• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.10
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• pp.34-42
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• 2012

This paper analyses the energy saving basic power models in core IP networks, and proposes the adaptive buffer and burst scheme which is a possible energy saving method, and its implementation algorithm in core IP networks. Especially this paper describes the adaptive buffer and burst scheme dynamically varying the buffering interval B according to the input traffic volume of ingress router, and explains the operation principle of proposed scheme. This method is to adjust the buffering interval B according to input traffic volume of ingress router, that is increasing the interval B when input traffic volume is low, and decreasing the interval B when input traffic volume is high between some given interval regions. This method can gets the high energy saving effect as decreasing the transition number of idle/active in networks when input traffic volume is low, and decreasing the transition number of idle/active by the continuous of burst packets in transit router when input traffic volume is high. This paper shows the increasing of asleep rate for the energy saving of core IP networks and confirms the energy saving of core IP networks by the computer simulation. We confirmed that proposed method can be save the energy of IP networks by properly trade off network performances.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.4
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• pp.699-712
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• 2000

Juam lake is a major water resource for the industrial and agricultural activities as well as the resident life of Kwangju and Chonnam regions. However, the water quality of the lake is getting worse due to a large quantity of pollutant inflowing to the lake. Thus, the strategy for achieving the water quality goal of the lake should be developed as soon as possible. When there are various alternatives that can be used as the strategy, several criteria based on the achievement degree of water quality goal, the applicability of technique and social environment, and the reasonableness of the cost required are made to evaluate and rank the alternatives. However, it is difficult to make a decision when there are multiple criteria and conflicting objectives and specifically the estimated values of criteria contain elements of uncertainty. The uncertainty stems from the lack of available information, the randomness of future situation, and the incomplete knowledge of expert. As the degree of uncertainty is higher, the decision becomes more difficult. In this study, a fuzzy decision-making method is presented to assist decision makers in evaluating various alternatives under uncertainty. The method allows decision makers to characterize the associated uncertainty by applying fuzzy theory and incorporate the uncertainty directly into the decision making process for selecting the "best" alternative so decisions can be made that are more appropriate and realistic than those made without taking uncertainty in account.

• Journal of International Area Studies (JIAS)
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• v.19 no.1
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• pp.157-204
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• 2015

This paper explores firm-specific internal and external determinants of the sustainability of "the social innovative enterprise(SIE)" by conducting a case research on Fragrant People Co. In doing so, some business and policy implications have been produced concerning the components and determinants of the sustainability of the SIE. First, entrepreneurship is a necessary factor for the survival and growth of the SIE. A social entrepreneur does manage effectively social and economic opportunities for making economic and social values interact dynamically beyond their trade-off relationship and creating new market chances. Second, the SIE also needs competitive advantages as commercial enterprises do. Valuable resources to be used for taking opportunities and avoiding threats, rare resources not to be possessed by other firms, and resources not to be easily imitated by competitors are extremely necessary for achieving objectives of the SIE. In addition, a firm must be well organized for those valuable, rare, and not easily imitated resources. Economic performance achieved by the SIE gives a birth to its financial independence, contributing to the realization of symmetric social performance. Third, the SIEs will be allowed to seek symmetrically economic and social performance only when they use sufficiently competitive advantage resources with entrepreneurship, which is composed of innovativeness, proactiveness, agility and risk-taking attitudes. In doing so, financial assistance from central or local governments may not ensure the sustainability of the SIEs. In addition, vision & value sharing(person-organization fit) can ensure the sustainability of the SIEs only when it is connected with the organizational commitment.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.42 no.1
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• pp.151-157
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• 2019

This study is about the process capability index (PCI). In this study, we introduce several indices including the index $C_{PR}$ and present the characteristics of the $C_{PR}$ as well as its validity. The difference between the other indices and the $C_{PR}$ is the way we use to estimate the standard deviation. Calculating the index, most indices use sample standard deviation while the index $C_{PR}$ uses range R. The sample standard deviation is generally a better estimator than the range R. But in the case of the panel process, the $C_{PR}$ has more consistency than the other indices at the point of non-conforming ratio which is an important term in quality control. The reason why the $C_{PR}$ using the range has better consistency is explained by introducing the concept of 'flatness ratio'. At least one million cells are present in one panel, so we can't inspect all of them. In estimating the PCI, it is necessary to consider the inspection cost together with the consistency. Even though we want smaller sample size at the point of inspection cost, the small sample size makes the PCI unreliable. There is 'trade off' between the inspection cost and the accuracy of the PCI. Therefore, we should obtain as large a sample size as possible under the allowed inspection cost. In order for $C_{PR}$ to be used throughout the industry, it is necessary to analyze the characteristics of the $C_{PR}$. Because the $C_{PR}$ is a kind of index including subgroup concept, the analysis should be done at the point of sample size of the subgroup. We present numerical analysis results of $C_{PR}$ by the data from the random number generating method. In this study, we also show the difference between the $C_{PR}$ using the range and the $C_P$ which is a representative index using the sample standard deviation. Regression analysis was used for the numerical analysis of the sample data. In addition, residual analysis and equal variance analysis was also conducted.

• Korean journal of applied entomology
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• v.61 no.1
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• pp.129-142
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• 2022

Nutrition dictates nearly all biological processes and determines Darwinian fitness in all living organisms, including insects. Research on insect nutrition has a long history in the field of insect physiology and the importance of understanding insect nutrition has become increasingly apparent with the growing need for producing insects as food and feed. Nevertheless, it is only in recent years that we have witnessed a major breakthrough in our knowledge of insect nutrition. The multivariate, interactive, and dynamic nature of nutrition has long hampered our complete understanding of insect nutrition. However, the challenge posed by such nutritional complexity has been overcome with the advent of the Nutritional Geometry, which is an integrative and multidimensional framework that enabled us to model complex interactions between multiple nutrients. In this review, we introduce the basic concepts and principles of the Nutritional Geometry and describe how this innovative framework has revolutionized the field of insect nutrition and has placed nutrition in the centre of the interface between physiology, ecology, and evolution. We close this review by discussing potentially fertile research areas that can benefit tremendously from the application of this powerful nutritional paradigm in the future.

• Journal of the Korean Electrochemical Society
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• v.25 no.4
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• pp.134-153
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• 2022

Regardless of a trade-off relationship between energy density and safety, it is essential to improve both properties for future lithium secondary batteries. Especially, to improve the energy density of batteries further, not only thickness but also weight of separators including ceramic coating layers should be reduced continuously apart from the development of high-capacity electrode active materials. For this purpose, an attempt to replace conventional slurry coating methods with a deposition one has attracted much attention for securing comparable thermal stability while minimizing the thickness and weight of ceramic coating layer in the separator. This review introduces state-of-the-art technology on ceramic-coated separators (CCSs) manufactured by the deposition method. There are three representative processes to form a ceramic coating layer as follows: chemical vapor deposition (CVD), atomic layer deposition (ALD), and physical vapor deposition (PVD). Herein, we summarized the principle and advantages/disadvantages of each deposition method. Furthermore, each CCS was analyzed and compared in terms of its mechanical and thermal properties, air permeability, ionic conductivity, and electrochemical performance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.66-79
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• 2016

A discussion has recently emerged over the increase of approvals of K-REITs, which is concluded on the basis of how to raise funds for business activity, fulfill the expected rate of return and maximize the management of managing investment funds. In addition, corporations need to acknowledge the necessity of the capital structure reflected in the current economic environment and decision-making processes. This research analyzed the characteristics by investment types and influence factors about the debt ratio of K-REITs. The data were collected from general management about business state, investment, and finance from 2002 to 2015 in K-REITs (except for the GFC period of 2007~2009). The results of the research demonstrated the high ratios of the largest shareholder characteristics, which are corporation, pension funds, mutual funds, banks, securities, insurance, and, recently, the increasing ratio of the largest shareholder and major stockholder. The investment of K-REITs is increasing the role of institutional investors that take a leading development of K-REITs. The behaviors of simultaneous investment of institutional investors were analyzed to show that they received higher interest rates than other financial institutions and ran in parallel with attraction and compensation. The results of the multiple regressions analysis, utilizing variables about debt ratio were as follows. The debt ratio showed a negative (-) relation that profitability is increasing, which matches the pecking order theory and trade off theory. On the other hand, investment opportunities (growth potential) showed a negative (-) relation and assets scale that indicated a positive (+) relation. The research results are reflected as follows. K-REITs focused on private equity REITs more than public offering REITs, and in the case of financing the capital of others, loan capital is operated under the guarantee of tangible assets (most of real estate) more than financing of the stock market. Further, after the GFC, the capital of others was actively utilized in K-REITs business, and the debt ratio showed that the determinant factors by the ratio and characteristics of the largest shareholder and investment products.

• Journal of Intelligence and Information Systems
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• v.24 no.3
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• pp.157-176
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• 2018

The purpose of this research is to develop a detection model for companies designated as administrative issue in KOSDAQ market using financial data. Administration issue designates the companies with high potential for delisting, which gives them time to overcome the reasons for the delisting under certain restrictions of the Korean stock market. It acts as an alarm to inform investors and market participants of which companies are likely to be delisted and warns them to make safe investments. Despite this importance, there are relatively few studies on administration issues prediction model in comparison with the lots of studies on bankruptcy prediction model. Therefore, this study develops and verifies the detection model of the companies designated as administrative issue using financial data of KOSDAQ companies. In this study, logistic regression and decision tree are proposed as the data mining models for detecting administrative issues. According to the results of the analysis, the logistic regression model predicted the companies designated as administrative issue using three variables - ROE(Earnings before tax), Cash flows/Shareholder's equity, and Asset turnover ratio, and its overall accuracy was 86% for the validation dataset. The decision tree (Classification and Regression Trees, CART) model applied the classification rules using Cash flows/Total assets and ROA(Net income), and the overall accuracy reached 87%. Implications of the financial indictors selected in our logistic regression and decision tree models are as follows. First, ROE(Earnings before tax) in the logistic detection model shows the profit and loss of the business segment that will continue without including the revenue and expenses of the discontinued business. Therefore, the weakening of the variable means that the competitiveness of the core business is weakened. If a large part of the profits is generated from one-off profit, it is very likely that the deterioration of business management is further intensified. As the ROE of a KOSDAQ company decreases significantly, it is highly likely that the company can be delisted. Second, cash flows to shareholder's equity represents that the firm's ability to generate cash flow under the condition that the financial condition of the subsidiary company is excluded. In other words, the weakening of the management capacity of the parent company, excluding the subsidiary's competence, can be a main reason for the increase of the possibility of administrative issue designation. Third, low asset turnover ratio means that current assets and non-current assets are ineffectively used by corporation, or that asset investment by corporation is excessive. If the asset turnover ratio of a KOSDAQ-listed company decreases, it is necessary to examine in detail corporate activities from various perspectives such as weakening sales or increasing or decreasing inventories of company. Cash flow / total assets, a variable selected by the decision tree detection model, is a key indicator of the company's cash condition and its ability to generate cash from operating activities. Cash flow indicates whether a firm can perform its main activities(maintaining its operating ability, repaying debts, paying dividends and making new investments) without relying on external financial resources. Therefore, if the index of the variable is negative(-), it indicates the possibility that a company has serious problems in business activities. If the cash flow from operating activities of a specific company is smaller than the net profit, it means that the net profit has not been cashed, indicating that there is a serious problem in managing the trade receivables and inventory assets of the company. Therefore, it can be understood that as the cash flows / total assets decrease, the probability of administrative issue designation and the probability of delisting are increased. In summary, the logistic regression-based detection model in this study was found to be affected by the company's financial activities including ROE(Earnings before tax). However, decision tree-based detection model predicts the designation based on the cash flows of the company.

• Korean Chemical Engineering Research
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• v.61 no.3
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• pp.378-387
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• 2023

Petrochemical is an energy consuming industry that consumes about 30% of total industrial energy consumption and is a representative carbon dioxide (CO₂) emission source. Among them, the Naphtha Cracking Center (NCC), which produces ethylene, propylene, propane and mixed C4, consumes large amounts of energy and emits significant amounts of CO₂. For this reason, an integrated techno economic- environmental impact assessment aimed at reducing energy consumption and environmental impact factors is necessary to ensure efficiency in terms of economics and environment. This study aims to analyze the efficiency of the heat exchanger network used in the existing NCC base on the pinch analysis and select an improvement plan that can reduced energy consumption. In order to reduces the utility consumption in the process, an optimal heat exchanger network considering the high-temperature and low-temperature stream was derived, and the economic evaluation was conducted by considering the trade-off between the reduction in utility consumption and the increase in heat exchanger installation cost. In addition, an environmental impact assessment was conducted on the reduced CO₂ emission in consideration of the environmental aspect, and the economic environmental impact assessment used the payback period to recover the invested funds to come up with an energy saving plan that can be applied based on the actual process. As a result of considering the economic-environmental impact assessment, when the environmental impact assessment was not considered, it was 4.29 months, 3.21 months, and 3.39 months for each case, and when considering the environmental impact assessment, it was 4.24 months, 3.17 months, and 3.35 months for each case. These results appeared equally both when the environmental impact assessment was not include and when it was include. In addition, a sensitivity analysis was conducted for each case to determine how important factors affect the payback period. As a result of the sensitivity analysis, the cost of the heat exchanger was identified as a major factor influencing the overall cost.

• Journal of Intelligence and Information Systems
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• v.20 no.1
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• pp.177-193
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• 2014

Over the past decade, there has been a rapid diffusion of electronic commerce and a rising number of interconnected networks, resulting in an escalation of security threats and privacy concerns. Electronic commerce has a built-in trade-off between the necessity of providing at least some personal information to consummate an online transaction, and the risk of negative consequences from providing such information. More recently, the frequent disclosure of private information has raised concerns about privacy and its impacts. This has motivated researchers in various fields to explore information privacy issues to address these concerns. Accordingly, the necessity for information privacy policies and technologies for collecting and storing data, and information privacy research in various fields such as medicine, computer science, business, and statistics has increased. The occurrence of various information security accidents have made finding experts in the information security field an important issue. Objective measures for finding such experts are required, as it is currently rather subjective. Based on social network analysis, this paper focused on a framework to evaluate the process of finding experts in the information security field. We collected data from the National Discovery for Science Leaders (NDSL) database, initially collecting about 2000 papers covering the period between 2005 and 2013. Outliers and the data of irrelevant papers were dropped, leaving 784 papers to test the suggested hypotheses. The co-authorship network data for co-author relationship, publisher, affiliation, and so on were analyzed using social network measures including centrality and structural hole. The results of our model estimation are as follows. With the exception of Hypothesis 3, which deals with the relationship between eigenvector centrality and performance, all of our hypotheses were supported. In line with our hypothesis, degree centrality (H1) was supported with its positive influence on the researchers' publishing performance (p<0.001). This finding indicates that as the degree of cooperation increased, the more the publishing performance of researchers increased. In addition, closeness centrality (H2) was also positively associated with researchers' publishing performance (p<0.001), suggesting that, as the efficiency of information acquisition increased, the more the researchers' publishing performance increased. This paper identified the difference in publishing performance among researchers. The analysis can be used to identify core experts and evaluate their performance in the information privacy research field. The co-authorship network for information privacy can aid in understanding the deep relationships among researchers. In addition, extracting characteristics of publishers and affiliations, this paper suggested an understanding of the social network measures and their potential for finding experts in the information privacy field. Social concerns about securing the objectivity of experts have increased, because experts in the information privacy field frequently participate in political consultation, and business education support and evaluation. In terms of practical implications, this research suggests an objective framework for experts in the information privacy field, and is useful for people who are in charge of managing research human resources. This study has some limitations, providing opportunities and suggestions for future research. Presenting the difference in information diffusion according to media and proximity presents difficulties for the generalization of the theory due to the small sample size. Therefore, further studies could consider an increased sample size and media diversity, the difference in information diffusion according to the media type, and information proximity could be explored in more detail. Moreover, previous network research has commonly observed a causal relationship between the independent and dependent variable (Kadushin, 2012). In this study, degree centrality as an independent variable might have causal relationship with performance as a dependent variable. However, in the case of network analysis research, network indices could be computed after the network relationship is created. An annual analysis could help mitigate this limitation.