• Journal of KIISE:Information Networking
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• v.36 no.1
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• pp.12-23
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• 2009

Sensor networks deployed in battlefields to support military operations or deployed in natural habitats to monitor the rare wildlifes must take account of protection of the location of valuable assets(i.e., soldiers or wildlifes) from an adversary or malicious tracing as well as the security of messages in transit. In this paper we propose a routing protocol GSLP(GPSR-based Source-Location Privacy) that is capable of enhancing the location privacy of an active source node(i.e., message-originating node) in the presence of multiple dormant sources(i.e., nodes lying nearby an asset whose location needs to be secured). Extended is a simple, yet scalable, routing scheme GPSR(greedy perimeter stateless routing) to select randomly a next-hop node with a certain probability for randomizing paths and to perform perimeter routing for detouring dormant sources so that the privacy strength of the active source, defined as safety period, keeps enhanced. The simulation results obtained by increasing the number of dormant sources up to 1.0% of the total number of nodes show that GSLP yields increased and nearly invariant safety periods, while those of PR-SP(Phantom Routing, Single Path), a notable existing protocol for source-location privacy, rapidly drop off as the number of dormant sources increases. It turns out that delivery latencies of GSLP are roughly less than two-fold of the shortest path length between the active source and the destination.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.5
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• pp.1460-1466
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• 2008

The purpose of this study is to verify how the accounting information of a bankrupt firm which is defined as a dishonor, an impaired total capital, a poor financial performance of a business, a rejection of auditor's opinion and an incongruity of auditor's opinion differs from that of a healthy firm on the basis of the index of financial affairs if the accounting information released by KOSDAQ is valuable. The sampling firms consists of 45 KOSDAQ firms that went bankrupt from 2000 to 2007 and 45 healthy firms which are selected in accordance with the sizes of assets. It has also selected the 30 sampling firms for the confirmation of the model in the same way. According to the result of the in-depth analysis, the variables related to security among the 17 indexes of financial affairs that have been used in this study for 5 years show a noticeable difference between a bankrupt firm and a healthy one. The accuracy of failed firms using this model for confirmation demonstrates 76.7% in 5 years before the bankruptcy, 76.7% in 4 years before that, 65.0% in 3 years before it, 76.7% in 2 years, 88.3% in 1 year. This data shows that the process from a healthy firm to a bankrupt one has progressed gradually and confirms the value of the index of financial affairs, exhibiting the accuracy with 83.8% of a presuming sample and 76.7% of a confirming sample for 5 years.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.600-608
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• 2017

This study analyzed the management index, debt ratio, and business performance of livestock agricultural farming corporations since the Korea international financial reporting standards (K-IFRS) was introduced in 2011. In addition, this study was based on credible accounting reports by the financial supervisory service's DART (data analysis, retrieval and transfer) system. First, after analyzing the key management index, the results showed that the current ratio, debt ratio, and current liabilities ratio decreased and the ratio of the owners increased on the safety index. Regarding the profitability index, the ROA (return on total assets), ROE (return on equity), and ROS (return on sales) increased slightly in 2014 compared to 2013. The overall growth and external growth on the growth index have not increased. Second, an analysis of the debt ratio and business performance, the debt ratio has a negative effect on the ROA and ROS. These results show that the use of debt of livestock agricultural farming corporations contributes to the external growth but it has a negative effect on business performance. These results show that management should consider solutions for the increase in sales to achieve cost reductions. In addition, the debt ratio should be reduced and solutions for an increase in revenue are needed to reduce management expenses, such as propagation of technical development.

• The Journal of Industrial Distribution & Business
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• v.9 no.5
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• pp.63-72
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• 2018

Purpose - This work analyzes, in detail, the specification of vector error correction model (VECM) and thus examines the relationships and impact among seven economic variables for USA - balance on current account (BCA), index of stock (STOCK), gross domestic product (GDP), housing price indices (HOUSING), a measure of the money supply that includes total currency as well as large time deposits, institutional money market funds, short-term repurchase agreements and other larger liquid assets (M3), real rate of interest (IR_REAL) and household credits (LOAN). In particular, we search for the main explanatory variables that have an effect on stock and real estate market, respectively and investigate the causal and dynamic associations between them. Research design, data, and methodology - We perform the time series vector error correction model to infer the dynamic relationships among seven variables above. This work employs the conventional augmented Dickey-Fuller (ADF) and Phillips-Perron (PP) unit root techniques to test for stationarity among seven variables under consideration, and Johansen cointegration test to specify the order or the number of cointegration relationship. Granger causality test is exploited to inspect for causal relationship and, at the same time, impulse response function and variance decomposition analysis are checked for both short-run and long-run association among the seven variables by EViews 9.0. The underlying model was analyzed by using 108 realizations from Q1 1990 to Q4 2016 for USA. Results - The results show that all the seven variables for USA have one unit root and they are cointegrated with at most five and three cointegrating equation for USA. The vector error correction model expresses a long-run relationship among variables. Both IR_REAL and M3 may influence real estate market, and GDP does stock market in USA. On the other hand, GDP, IR_REAL, M3, STOCK and LOAN may be considered as causal factors to affect real estate market. Conclusions - The findings indicate that both stock market and real estate market can be modelled as vector error correction specification for USA. In addition, we can detect causal relationships among variables and compare dynamic differences between countries in terms of stock market and real estate market.

• The Journal of Industrial Distribution & Business
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• v.11 no.7
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• pp.29-40
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• 2020

Purpose: In modern society, many urban problems are occurring, such as aging, hollowing out old city centers and polarization within cities. In this study, we intend to apply big data and machine learning methodologies to predict depression symptoms in the elderly population early on, thus contributing to solving the problem of elderly depression. Research design, data and methodology: Machine learning techniques used random forest and analyzed the correlation between CES-D10 and other variables, which are widely used worldwide, to estimate important variables. Dependent variables were set up as two variables that distinguish normal/depression from moderate/severe depression, and a total of 106 independent variables were included, including subjective health conditions, cognitive abilities, and daily life quality surveys, as well as the objective characteristics of the elderly as well as the subjective health, health, employment, household background, income, consumption, assets, subjective expectations, and quality of life surveys. Results: Studies have shown that satisfaction with residential areas and quality of life and cognitive ability scores have important effects in classifying elderly depression, satisfaction with living quality and economic conditions, and number of outpatient care in living areas and clinics have been important variables. In addition, the results of a random forest performance evaluation, the accuracy of classification model that classify whether elderly depression or not was 86.3%, the sensitivity 79.5%, and the specificity 93.3%. And the accuracy of classification model the degree of elderly depression was 86.1%, sensitivity 93.9% and specificity 74.7%. Conclusions: In this study, the important variables of the estimated predictive model were identified using the random forest technique and the study was conducted with a focus on the predictive performance itself. Although there are limitations in research, such as the lack of clear criteria for the classification of depression levels and the failure to reflect variables other than KLoSA data, it is expected that if additional variables are secured in the future and high-performance predictive models are estimated and utilized through various machine learning techniques, it will be able to consider ways to improve the quality of life of senior citizens through early detection of depression and thus help them make public policy decisions.

• Journal of Korean Society of Transportation
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• v.25 no.3
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• pp.55-63
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• 2007

This paper analyzes the relative efficiency of Korea's logistics industry with the DEA-ANP model from 2003 to 2005. To measure the efficiency, this paper used the numbers of employees, fixed assets. total capital. and operating costs as input factors and sales amounts and net incomes as output factors. The average efficiency score of the entire logistics industry is 0.175, so most logistics companies in Korea should improve their current inefficiencies. The industry with the highest efficiency score is marine transportation. with an average three-year efficiency score of 0.3692. In terms of sales and high efficiency. most of the highest-ranked companies belong to the marine transportation industry, so marine transportation has the most influence on raising the efficiency score of Korea's logistics industry. To improve the inefficiency of inputs that exists overall in the logistics industry it is necessary to control excessive numbers of employees. To improve the amount of sales, it is necessary to make a policy of satisfying various logistics demands, continuous investments, and attracting foreign logistics demand: such things will help strengthen the international competitiveness of Korea's logistics industry.

• The Korean Journal of Financial Management
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• v.20 no.1
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• pp.29-60
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• 2003

This study investigates the certification role by the types of venture capitalists in KOSDAQ IPOs. The sample covers 88 venture companies listed on KOSDAQ from January, 1997 to December, 2001. The major results are as follows. Firstly, IPOs of firms backed by New Technology Business Investment Companies are less underpriced than those of firms backed by Small Business Investment Companies. The underpricing difference between two groups is statistically significant. This sheds light on the evidence of the certification role of venture capitalist in KOSDAQ IPOs market. Secondly, our result also attests the certification role by the types of venture capitalists among Small Business Investment Company. IPOs backed by yen拉re capitalists of financial institutions are less underpriced than those backed by venture capitalists of individual wealthy investors. The underpricing difference between two groups is statistically significant. Finally, underpricing of New Technology Business Investment Company-backed IPOs is less than that of Small Business Investment Company-backed IPOs. In addition, we found that the size of underpricing is affected by business history, sub-scription ratio, and total assets prior to registration.

• Journal of Navigation and Port Research
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• v.39 no.1
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• pp.69-75
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• 2015

The concrete purpose of this study is to suggest actually a debt ratio to optimize the capital structure providing a kind of approach to estimate the proper debt ratio with an analytical model and empirical data in Korean shipping industry. The mathematical and analytical model is started from the first equation about ROE, return of net operating income on equity, with an independent variable, debt ratio. It is constructed with several parameters, ROS(return of operating income on sales), TAT(total assets turnover), and NFCL(net finance cost to liabilities). There could not be a certain relationship between debt ratio and ROS or TAT, while some correlation or causality between debt ratio and NFCL. In other words, most of firms with high debt ratio is likely to burden higher finance cost than others with low one. In this case, there is a linearity relationship between debt ratio and NFCL, so then the second equation considering this relation could be included within the analytical approach of this paper. To be short, if the criteria of adequate debt ratio has to be defined as some level of debt ratio to optimize ROE, the ROE could be illustrated as a quadratic equation to debt ratio from two equations. Next, this research estimated those parameters' numbers through the single regression method with data over 12 years of Korean shipping industry, and identified empirically the fact that optimal debt ratio would be approximately 400%. To conclude, if that industry's sales and operating incomes are stable, the debt ratio could be accepted until twice of 200% had forced in order to guarantee its financial safety in past time.

• Journal of Distribution Science
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• v.12 no.12
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• pp.55-63
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• 2014

Purpose - In urban regeneration projects, considerations for rejuvenating traditional public markets are becoming increasingly important. That is because the traditional market is not just a commercial space but also a living center for local people's existence. Cultural contents like these are invaluable assets in the contemporary economy. However, traditional markets are gradually declining because of changes in distribution systems and consumer lifestyles. New distribution systems such as modern distribution markets, home shopping, and online shopping malls made traditional markets less competitive. Further, traditional markets have not been able to adapt to the changing consumption styles of younger generations. Some say that it is a natural phenomenon that cannot be stopped. However, traditional markets are not just another distribution system but also a valuable resource that encapsulates the local people's tradition and history. Thus, a revitalization strategy for traditional public markets has become an urgent task in contemporary urban regeneration projects. This study aimed to find ways to activate traditional public markets by making it a community landmark based on visual merchandising perspectives. Research design and methodology - This study focused on analyzing Granville Island (Vancouver, Canada) as a role-model project for rejuvenating the traditional market. It investigated Granville Island both with walk-through evaluation and literature reviews. Results - We found that it has been developed not only to improve visual aspects, but also to promote cultural contents with high value added. For example, the developers maintained the visual elements that tell the original history of the site as an industrial factory. The renewal project had a balance between improving the outer look and creating attractive contents. The following are the merits of Granville Island that Korean traditional markets should note. First, they kept the whole area clean and hygienic. Second, merchants are well educated, business-savvy, and consumer-oriented. Third, the area's total environmental designs were done by professionals of a high caliber. Fourth, the city government and the merchants'association were collaborating well in their efforts to accommodate the changing needs of consumers. Conclusions - This study made the following suggestions as a conclusion. First, it will be a very powerful tool to rejuvenate the traditional market if we can discover unique cultural resources and develop them as cultural products, experiences, and events. Consumers of the 21st century have a strong tendency to consume not only material products, but also the experiences and memories attached to them. Second, in order to maintain the unique characteristics of traditional markets, fostering the viability of the merchants' association and local residents' society would be essential. Third, it is necessary to make the traditional market into a cultural place not only for the shopping patronage of local residents, but also for attracting tourists to increase sales. Finally, professional management and design approaches are needed in order to make the traditional market a pleasant space from a visual merchandising standpoint.

• The Journal of the Korea Contents Association
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• v.11 no.5
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• pp.403-412
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• 2011

This study aims at proposing clear direction of tourism policy through analyzing the correlation between tourism resource, tourism system and activation of regional economic. A total of 283 samples were ultimately collected in survey of 300 researchers from the national and public institutes in provinces Chungchong-do and Kyungsang-do in July 2010 alone. SPSS 15.0 and AMOS 6.0 were used to test the model. Analysis showed that the more regional tourism resources have more significant effect on tourism system and tourist-attracting strategy, and that tourism system exerts influence on tourist-attracting strategy. So it was proved that the tourism policy effects meaningfully on vitalization of regional economic, and it was confirmed that the tourism system is more effective on the energization of regional economic than the tourist-attracting strategy. But the hypothesis has been rejected unexpectedly that tourist attractions have consequences for the activation of regional economic. It establishes the fact that it is useless for regional economy regardless of abundant regional tourism resources, if the tourism policy is not concretely in force. Therefore, Korean government must intercept overissue and overlapping investments on tourism development by the local government and induce qualitative growth of tourism sector through upgrading of development guidelines and the criteria for selecting tourism special zone, regional festival and cultural assets, and its continuous assessment and management. And it is desirable to enforce the connected cooperation projects between local governments and the 5+2 great-sphere economic blocs on government-level.