• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.6
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• pp.3-13
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• 2010

Differential Fault Analysis (DFA) is widely known for one of the most efficient method analyzing block cipher. In this paper, we propose a new type of DFA on DES (Data Encryption Standard). DFA on DES was first introduced by Biham and Shamir, then Rivain recently introduced DFA on DES middle rounds (9-12 round). However previous attacks on DES can only be applied to the encryption process. Meanwhile, we first propose the DFA on DES key-schedule. In this paper, we proposed a more efficient DFA on DES key schedule with random fault. The proposed DFA method retrieves the key using a more practical fault model and requires fewer faults than the previous DFA on DES.

• Korea Journal of Hospital Management
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• v.25 no.4
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• pp.13-28
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• 2020

Purposes: The purpose of this study is to analyze the institutional and personal factors that affect the medical utilization of patients transferred to tertiary medical institutions. Methodology: We retrospectively analyzed the 2 weeks electronic medical records of 1,556 patients, who were referred to the tertiary hospital, from June 15 to 26, 2015. The patient's personal characteristics, referral hospital, referral path, medical experiences and expenses were analyzed for 6 months after the patient's first visit. Findings: The largest proportion (848; 54.5%) of referrals was referred from primary clinic but the referrals of the same tertiary hospital level were one in seven (228; 14.7%) of the patients. Most patients (1,401; 90%) were referred from the clinics and hospitals directly and only one in ten (155; 10%) of the patients utilized the medical referral center. Patients who had been referred from tertiary care institutions had significantly higher medical costs than those referred to primary care (7,560,000 vs 2,333,000 won). The institutional factors including the numbers of visits to outpatient clinic, previous history of hospitalization and operation, consultation to other medical departments and hospitalization fee significantly influenced on medical utility pattern. Personal factors including patient's medical diagnosis and department of disease have a highly correlation with patient's referrals. Practical implications: The medical utilization of medical expenses and experiences is influenced by institutional and individual factors, and it is important to establish a referral system considering the institutional factors of the type of referral hospital.

• Knowledge Management Research
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• v.22 no.2
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• pp.55-76
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• 2021

The real estate market is a representative imperfectly competitive market. Real estate information is characterized by being collected and utilized in a closed environment, and market participants have to pay a lot of time, effort, and costs to acquire such information. Korea's real estate public data is increasing year by year, but it is scattered by relevant ministries. So it is difficult to search and analyze, and the level of development of the industry using it is low. In the recent 4th industrial revolution, the proptech industry has developed as an industry to efficiently provide necessary information to the real estate market. In this study, based on the case of major companies in the real estate platform field among proptech companies, we looked at the types of information provided to users, and on the contrary, explored ways to utilize the data collected from users. The results of this study are expected to provide theoretical and practical implications for ways to reduce information asymmetry in the real estate market and contribute to the development of the real estate industry.

• Journal of Industrial Convergence
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• v.18 no.6
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• pp.9-17
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• 2020

COVID19 is causing many fundamental phenomena all over the world. Since January 2020, the number of confirmed medical examinations has increased significantly worldwide, and the medical systems in each country have become paralyzed. South Korea has taken a proactive approach and is doing well, befitting the name K-Peace Prevention. However, it can be said that there is still a lack of awareness of legal and administrative limits. In this study examines the shortcomings and limitations of the laws relevant to the current infectious disease prevention and management systems from the perspective of criminal policy based on the "Infectious Disease Control and Prevention Act," and comparatively analyzes the laws in advanced countries to propose effective and practical criminal policy response measures for the prevention and control of infectious diseases.

• Korea Journal of Hospital Management
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• v.26 no.1
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• pp.71-82
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• 2021

Purpose: The purpose of this study is to estimate incomes and costs of the medical clinics by using secondary data. Methodology: The medical incomes and costs were estimated from 405 clinics operated by sole practitioner providing out-patient services among all clinics subject to the Medical Cost Survey on National Health Insurance Patients in 2017, excluding dental clinics and oriental medical clinics. The incomes and costs of the medical clinics were reflected with incomes and costs of health insurance benefits and were calculated by types of medical services (i.e., basic care, surgery, general treatment, functional test, specimen test and imaging test). The costs were classified as follows: labor costs, equipment costs, material costs and overhead costs. Secondary data was used to estimate the incomes and costs of the medical clinics. For allocation bases for costs for each type of the medical service, the ratio of revenue from health insurance benefits by types of medical services was applied. However, labor costs were calculated with the activity ratio by types of medical services and occupations, using clinical expert panel data. Finding: The percentage of health insurance income for all medical income was 73.1%. The health insurance cost per clinic was 401,864 thousand won. Labor cost accounted for the largest portion of the health insurance income was 191,229 thousand won (47.6%), followed by management cost was 170,018 thousand won (42.3%), materials cost was 35,434 thousand won (8.8%), and equipment costs was 5,183 thousand won (1.3%). Practical Implications: This study suggests a method of estimating incomes and costs of medical clinic services by using secondary data. It could efficiently provide incomes and costs to assess an appropriate level of the health insurance fee to the clinics.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.4
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• pp.113-127
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• 2021

Topic modeling has been receiving much attention in academic disciplines in recent years. Topic modeling is one of the applications in machine learning and natural language processing. It is a statistical modeling procedure to discover topics in the collection of documents. Recently, there have been many attempts to find out topics in diverse fields of academic research. Although the first Department of Industrial Engineering (I.E.) was established in Hanyang university in 1958, Korean Institute of Industrial Engineers (KIIE) which is truly the most academic society was first founded to contribute to research for I.E. and promote industrial techniques in 1974. Korean Society of Industrial and Systems Engineering (KSIE) was established four years later. However, the research topics for KSIE journal have not been deeply examined up until now. Using topic modeling algorithms, we cautiously aim to detect the research topics of KSIE journal for the first half of the society history, from 1978 to 1999. We made use of titles and abstracts in research papers to find out topics in KSIE journal by conducting four algorithms, LSA, HDP, LDA, and LDA Mallet. Topic analysis results obtained by the algorithms were compared. We tried to show the whole procedure of topic analysis in detail for further practical use in future. We employed visualization techniques by using analysis result obtained from LDA. As a result of thorough analysis of topic modeling, eight major research topics were discovered including Production/Logistics/Inventory, Reliability, Quality, Probability/Statistics, Management Engineering/Industry, Engineering Economy, Human Factor/Safety/Computer/Information Technology, and Heuristics/Optimization.

• Korea Journal of Hospital Management
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• v.26 no.4
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• pp.51-58
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• 2021

Purpose: This study is based on the results of previous studies that falls, which is a frequent social problem, causes physical, mental and social health problems in the elderly. In order to identify risk factors for falls in the elderly, this study derives a relationship with oral health and proposes the necessity of oral health care as part of countermeasures to prevent falls in the elderly. Methodology: The final 6,936 people were analysed using the 2018 Korean Longitudinal Study of Ageing(KLoSA) survey data, and the analysis was conducted using the multiple logistic and multiple regression analysis to investigate the relationship between Geriatric Oral Health Assessment Index (GOHAI) and falls experience. Findings: As a result of the analysis in this study, the number of falls experiences and whether or not falls were higher in the elderly female group than in the male group. The likelihood of falls experience has been statistically reduced as Geriatric Oral Health Assessment Index increases by one unit.(OR : 0.991) The number of falls has also been statistically reduced as Geriatric Oral Health Assessment Index increase by one unit.(B : -0.001) Practical Implications: The results of this study, which showed that higher Geriatric Oral Health Assessment Index was lower risk of falls, explained by the connection that oral health may affect nutritional intake, which leads to sarcopenia and physical loss, which in turn increases the risk of falls. As a way to solve the fall problem, efforts should be made to improve the oral health of the elderly, and furthermore, the importance of nutrition management thorugh oral health care of the elderly is increasd.

• Journal of Korea Society of Digital Industry and Information Management
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• v.18 no.2
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• pp.93-110
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• 2022

The purpose of this study is to explore business investment and operation of O2O (Online-To-Offline) combined service. The study will analyze the necessary factors for growing the business by dividing the O2O service by industry. The Online-to-Offline is a method of inducing purchases of products and services by connecting between online and offline This research methodology organized the four stages of the analysis process. The analysis of all stages was performed with association rules in big data techniques. It is divided into the start-up period, growth period, maturity period, and decline period, and analysis is conducted on the business investment, expenditure cost, business operation, and conflict factors. As the research result, the first analysis has shown commonality with government subsidies, bank loans, and personal funds in all industries. The second analysis showed a lot of expenditure on labor costs of internal employees, marketing/sales, facility facilities, equipment, and equipment purchase costs. The third analysis showed difficulty in raising the investment resources necessary for business operations in all industries. The last analysis showed conflicts in the industry, businesses license, legal systems, and small business owners in all industries. This study contributed to the abundance and diversity of research methodologies in management information systems using association rules. In addition, the description of organizational development theory was updated while explaining the business investment and operation of O2O combined services. In practical implication, the O2O services include environmental factors that cause convergence between industries. Accordingly, this is required for new O2O services through new laws and systems and reorganization of existing laws and regulations.

• Journal of Korea Trade
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• v.24 no.6
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• pp.37-60
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• 2020

Purpose - The purpose of this study is to investigate the direct and indirect impact of innovation space factors on the growth of semiconductor enterprises. Design/methodology - This empirical study uses the financial statements of 83 semiconductor listed companies in 23 provinces from 2004 to 2019 approved by CSRC (2019). A stepwise regression and backward regression are employed in order to examine the role of innovation space to expand technology investment in promoting business growth and uses South Korean Samsung's investment in China as a test case. Findings - Results indicate that innovation space, technology input, geographical area, owner's background, operating years and financing liabilities all contribute to a boost in business growth. Factors such as carbon emission, financial liberalization, government efficiency, technology input, and financing liabilities further influence management growth. Innovation space follows a nonlinear pattern, and this plays a positive role in magnifying the influence of technology on management growth. Additionally, operations of the state-owned companies and expansionary financing enterprises are influenced by the external economy. Regarding the spatial distribution, the Samsung investment in 24 companies in China shows that Samsung focuses on the acquisition of scarce resources for semiconductor production as a component of its investment and innovation strategy. Originality/value - Even though prior research has considered the concepts studied here, this study contributes to empirically evaluate the direct impact of innovation space on business growth, and the indirect impact of innovation space on business growth through technology investment. This study includes an in-depth discussion of the practical effects that innovation space has on China's economy, using a case of South Korean Samsung's investment in China as a test the empirical findings.

• Journal of Korea Society of Digital Industry and Information Management
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• v.18 no.4
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• pp.97-110
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• 2022

The purpose of this study is to analyze the level of public data convergence capabilities of administrative organizations and to explore important variables in data-based organizational capabilities. The theoretical background was summarized on public data and use activation, joint use, convergence, administrative organization, and convergence constraints. These contents were explained Public Data Act, the Electronic Government Act, and the Data-Based Administrative Act. The research model was set as the data-based organizational capabilities effect by a data-based administrative capability, public data operation capabilities, and public data operation constraints. It was also set whether there is a capabilities difference data-based on an organizational operation by the level of data convergence capabilities. This study analysis was conducted with hierarchical cluster analysis and multiple regression analysis. As the research result, First, hierarchical cluster analysis was classified into three groups. It was classified into a group that uses only public data and structured data, a group that uses public data on both structured and unstructured data, and a group that uses both public and private data. Second, the critical variables of data-based organizational operation capabilities were found in the data-based administrative planning and administrative technology, the supervisory organizations and technical systems by public data convergence, and the data sharing and market transaction constraints. Finally, the essential independent variables on data-based organizational competencies differ by group. This study contributed. As a theoretical implication, this research is updated on management information systems by explaining the Public Data Act, the Electronic Government Act, and the Data-Based Administrative Act. As a practical implication, the activity reinforcement of public data should be promoting the establishment of data standardization and search convenience and elimination of the lukewarm attitudes and Selfishness behavior for data sharing.