• Journal of Chest Surgery
• /
• v.35 no.3
• /
• pp.209-216
• /
• 2002

Background: Valvular heart disease is still the most common health problem in Korea. By the end of the year 1999, there has been 94,586 cases of open heart surgery since the first case in 1958. Among them, 36,247 cases were acquired heart diseases and 20,704 of those had valvular heart disease. But there was no database system and every surgeon and physician had great difficulties in analysing and utilizing those tremendous medical resources. Therefore, we developed a valve registry database program and utilize it for risk factor analysis and so on. Material and Method: Personal computer-based multiuser database program was created using Microsoft AccessTM. That consisted of relational database structure with fine-tuned compact field variables and server-client architecture. Simple graphic user interface showed easy-to-use accessability and comprehensibility. User-oriented modular structure enabled easier modification through native AccessTM functions. Infinite application of query function aided users to extract, summarize, analyse and report the study result promptly. Result: About three-thousand cases of valve replacement procedure were performed in our hospital from 1968 to 1999. Total number of prosthesis replaced was 3,700. The numbers of cases for mitral, aortic and tricuspid valve replacement were 1600, 584, 76, respectively. Among them, 700 patients received prosthesis in more than two positions. Bioprosthesis or mechanical prosthesis were used in 1,280 and 1,500 patients respectively Redo valve replacements were performed in 460 patients totally and 40 patients annually Conclusion: Database program for registry of valvular heart disease was successfully developed and used in personal computer-based multiuser environment. This revealed promising results and perspectives in database management and utilization system.

• Journal of Internet Computing and Services
• /
• v.13 no.2
• /
• pp.59-71
• /
• 2012

PKI-based public key scheme is outstanding in terms of authenticity and privacy. Nevertheless its application brings big burden due to the certificate/key management. It is difficult to apply it to limited computing devices in WSN because of its high encryption complexity. The Bilinear Pairing emerged from the original IBE to eliminate the certificate, is a future significant cryptosystem as based on the DDH(Decisional DH) algorithm which is significant in terms of computation and secure enough for authentication, as well as secure and faster. The practical EC Weil Pairing presents that its encryption algorithm is simple and it satisfies IND/NM security constraints against CCA. The Random Oracle Model based IBE PKG is appropriate to the structure of our target system with one secret file server in the operational perspective. Our work proposes modification of the Weil Pairing as proper to the closed network for secret file distribution[2]. First we proposed the improved one computing both encryption and message/user authentication as fast as O(DES) level, in which our scheme satisfies privacy, authenticity and integrity. Secondly as using the public key ID as effective as PKI, our improved IBE variant reduces the key exposure risk.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.12 no.1
• /
• pp.25-31
• /
• 2017

The objective of this study is to find the failure factors of venture companies. We analyze 210 troubled venture companies, all of which have been under guarantee from the Korea Technology Finance Corporation over the last three years. Methods of analysis for failure factors are as follows. First, we categorize the failure factors into the four different types based on growth and profitability indicators in the financial statements of targeted venture companies. Then we analyzed the failure factors of the subject companies based on the troubled guarantee reports made by the Korea Technology Finance Corporation. If a venture company under its guarantee program falls into insolvency, the Korea Technology Finance Corporation make the troubled guarantee report to find out the failure factors and evaluate the recovery potentials. We identify 374 failure factors of venture companies through the analysis. The most prominent among them are deteriorating of business environments (79 factors) and decreasing or withdrawing orders from major suppliers (54 factors) due to bankruptcies or change in business plans. They are followed by slowing collection of accounts receivable (31 factors), dropping or frozen product price (24 factors) due to intensifying competition and escalating pressures from major suppliers, rising raw material costs both at home and abroad (21 factors). In addition, the nuclear power plant disaster in Japan, shut-down of the Kaesong Industrial Complex and subsequent lawsuits, delay in technology development projects, high cost-low efficiency management structure, etc., are also revealed as new factors causing trouble for venture companies.

• Journal of Korean Academy of Nursing Administration
• /
• v.6 no.3
• /
• pp.333-345
• /
• 2000

The health care environment becomes more competitive every day. It has fallen to nurse managers - from vice presidents of patient care to nurse managers and their assistants - to recruit and develop a workforce that successfully meets the needs of both patients and the organization. This means employees who demonstrate advanced critical thinking skills, creative problem solving, and sound decision making skills combined with clinical skills and patient advocacy. The environment which nurse managers create and the way they relate to their workforce, are pivotal to organizational viability. Especially leadership of first -line nurse managers contributes to the success of their organizations. First-line nurse managers are deserved to be one of the most administrative supervisors through the middle stratum in a hospital organization as being a manager in the field service if assessed from the overall aspects of hospital, as being an interim managers in the nursing department as well as being a supreme supervisor in a unit in terms of an organizational structure in the hospital. Similarly, as a compete leader, the first-line nurse managers have not only a professional which is qualified to perform a role of appropriate coordination with medical staff and key personnel but also hold an important key position a being responsible for performing his or her given role. The first-line nurse manager is expected to manage human and fiscal resources in ways not required before. While an identified need for well-prepared first-line nurse manager continues to plague the profession, first-line nurse managers often have difficulty providing the leadership required. The need leadership training to function effectively in their positions. But we hardly find a useful leadership training program for first-line nurse managers, therefore the purpose of this study was to developed the leadership training program for them. The steps of leadership program development were below: 1st step, 2 studies were done before develop a leadership program. One was done to ask to first-line nurse managers what they want to learn through leadership training, the other one was to ask the staff nurses what their opinions are for their first-line nurse managers leadership. 2nd step was searching other leadership programs contents. The results of this study were below: The total amount of hours is 24. Leadership training program contents are : Future of nursing profession (210min), understanding basic factor's of leadership and leadership theories(310 min), self understanding as first- line nurse managers(320 min), basic principle and practice of interpersonal relationship(210 min), assertiveness training, conflict management (180min), and group study(210min). This is challenging time to be a leader, especially in nursing. As nurse managers look toward the new millennium, it seems as through the same struggles are ahead that are behind. So nurse managers need to embrace change with a positive attitude. They need to demonstrate risk taking and support it in their staffs. All these things are possible that after they participate the leadership training program.

• Journal of the Korean Society of Radiology
• /
• v.12 no.2
• /
• pp.209-216
• /
• 2018

In the field of angiography and interventional radiology, it is said that the risk of radiation exposure to the eyes is high due to the characteristics of work, but currently divided dose assessment and management are not carried out in reality. Therefore, in this study, in order to evaluate the dose of the operator in the surgical environment and to analyze the shields, firstly, we selected the point where the operator is mainly located, evaluated the exposure dose of the eye after attaching the pocket dosimeter to the lateral angle point of the head and neck phantom, and evaluate shielding effect when wearing lead glasses that is currently commercialized. Secondly, we evaluated the tendency of the exposure dose of the eye and the shielding effect through simulation in the same geometric structure as the actual measurement. As a result, in the case of measurement using a dosimeter, the cumulative dose increased with the increase of the fluoroscopic time, and the tendency was different according to the position of the operator. Simulation results show that the dose distribution of the eye lens in the mathematical phantom is about 1.1 ~ 1.3 times higher than that of the cornea. Also, The protective effect of the lead glasses showed a shielding effect of at least 3.7 ~ 21.4% in each eye.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.37 no.1
• /
• pp.29-41
• /
• 2017

Design rainfalls are one of the most important hydrologic data for river management, hydraulic structure design and risk analysis. The design rainfalls are first estimated by a point frequency analysis and the IDF (intensity-duration-frequency) curve is then constructed by a nonlinear regression to either interpolate or extrapolate the design rainfalls for other durations which are not used in the frequency analysis. It has been widely recognised that the more reliable approaches are required to better account for uncertainties associated with the model parameters under circumstances where limited hydrologic data are available for the watershed of interest. For these reasons, this study developed a hierarchical Bayesian based GLM (generalized linear model) for a regional frequency analysis in conjunction with a scaling function of the parameters in probability distribution. The proposed model provided a reliable estimation of a set of parameters for each individual station, as well as offered a regional estimate of the parameters, which allow us to have a regional IDF curve. Overall, we expected the proposed model can be used for different aspects of water resources planning at various stages and in addition for the ungaged basin.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.27 no.5
• /
• pp.574-583
• /
• 2021

Predicting shipping markets is an important issue. Such predictions form the basis for decisions on investment methods, fleet formation methods, freight rates, etc., which greatly affect the profits and survival of a company. To this end, in this study, we propose a shipping freight rate prediction model for container ships using gated recurrent units (GRUs) and long short-term memory structure. The target of our freight rate prediction is the China Container Freight Index (CCFI), and CCFI data from March 2003 to May 2020 were used for training. The CCFI after June 2020 was first predicted according to each model and then compared and analyzed with the actual CCFI. For the experimental model, a total of six models were designed according to the hyperparameter settings. Additionally, the ARIMA model was included in the experiment for performance comparison with the traditional analysis method. The optimal model was selected based on two evaluation methods. The first evaluation method selects the model with the smallest average value of the root mean square error (RMSE) obtained by repeating each model 10 times. The second method selects the model with the lowest RMSE in all experiments. The experimental results revealed not only the improved accuracy of the deep learning model compared to the traditional time series prediction model, ARIMA, but also the contribution in enhancing the risk management ability of freight fluctuations through deep learning models. On the contrary, in the event of sudden changes in freight owing to the effects of external factors such as the Covid-19 pandemic, the accuracy of the forecasting model reduced. The GRU1 model recorded the lowest RMSE (69.55, 49.35) in both evaluation methods, and it was selected as the optimal model.

• The Korean Journal of Archival Studies
• /
• no.52
• /
• pp.119-170
• /
• 2017

This study aims to analyze the environment for the open-source records system and to identify the risk and requirements for the success of the strategy in Korea. For this, Chapter 2 presented a review of the strategic benefits of open source to public organizations, developers, and users. It also discussed the process of cooperatively developing and releasing the source code and the technology infrastructure supporting open source. In Chapter 3, six representative open-source projects in the field of records management were selected, and case studies were conducted. To derive comprehensive implications, we have divided the main development body of open-source projects into international organizations, international cooperation systems, national archives, and software development companies. We also analyzed the background and purpose of each project, the agents of development and funding, the governance model, the development period and cost, the business model and software architecture, the community composition, and the licensing strategy. Through this, we have derived four critical success factors. In terms of technology, a component-based design was required; therefore, we proposed a microservice architecture and a model-view-controller design pattern. Next, it was necessary to reestablish system requirements of records center and archives. Moreover, we also proposed a dual licensing strategy to allow developers to easily participate in open-source projects. Lastly, we emphasized a strong governance structure and an effective cooperation framework to create a sustainable community. For a record system to be open-source successfully in an organization-centered market, the roles of software developers and end users should be exercised more in the community. To achieve this, it is important to build various collaborative tools and development infrastructure from a planning stage to a centralized one.

• Journal of the Korean Institute of Gas
• /
• v.25 no.6
• /
• pp.35-44
• /
• 2021

The PR (Photo Resist) process in the semiconductor process is a process that uses a mixture of flammable substances. Due to the process equipment is installed in a clean room and when flammable substances leak, there is a high risk of suffocation, fire, and explosion. It is necessary to analyze the impact of accidents that may occur during operation and to evaluate whether the safety of workers can be guaranteed. In this study, the value of radiant heat and temperature change at the monitor point set up virtual inside the clean room was confirmed through CFD simulation of 10 leak and fire scenarios using the FLACS CFD - Fire Module. A fire that occurs inside a clean room transfers high radiant heat to the inter-story structure, but its scope is quite limited, and it is unlikely that it will collapse in a single fire accident. There was no scenario in which two stairs leading to the exit were exposed to high radiant heat at the same time due to a fire accident, therefore workers were able to escape in case of a fire. In addition, it was confirmed that the level of radiant heat and temperature rise rapidly decreased as they moved downstairs. According to the API 520 standard, workers exposed to 6.31 kW/m² of radiant heat that workers can withstand for 30 seconds were confirmed that it was possible to sufficiently escape from the inside.

• Journal of Environmental Impact Assessment
• /
• v.31 no.5
• /
• pp.286-295
• /
• 2022

In this study, the concentration distribution of indoor radon in Daejeon Metropolitan City was investigated and the reduction efficiency was evaluated by applying the radon reduction methods. Based on the results of the National Institute of Environmental Research, indoor radon measurements were conducted on 24 selected houses, and the average value of District A was 261 Bq/m3, far exceeding the standard, and even in the same house, indoor radon concentration was affected by measurement point and time. In the case of eight houses that applied the soil venting method to reduce radon, the indoorradon level was significantly lowerthan the standard value, and the average reduction efficiency was also around 55%, indicating a good reduction effect. In addition, the average reduction efficiency was around 90% in the two houses that carried out the shielding method, showing the very excellent effect of the indoorradon reduction. Even if the same reduction method is applied when reducing radon, the reduction efficiency may vary depending on various factors such as the structure of the building, the frequency of ventilation, and the season, so it is necessary to accurately evaluate the effectiveness of the reduction method in the future. Based on this, it is necessary to establish indoor radon management measures in Daejeon Metropolitan City to reduce human harm caused by radon exposure.