• Journal of Applied Reliability
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• v.14 no.4
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• pp.213-219
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• 2014

Wind turbine, which is attracting part of the renewable energy and is researching continuously, is going to be large size for high efficiency. There is a yaw system rotating the nacelle, weighted about 600 tons, to be perpendicular with the wind direction blowing in the large wind turbine. The wind turbine is focusing on the reliability improvement because working environment effect is bigger than any other points and specially, the reliability improvement of the yaw drive is required by the customer because it is the key component of the wind turbine. Because of this, the establishment of criteria for yaw drive is required because yaw drive system is the part of the wind turbine closely related with ensuring the reliability. So, this study did the failure analysis of the yaw drive system, which is consisted with 10 sets of yaw drives through researching and analyzing the site conditions. Also this study designed the life test method based on the failure analysis and working condition of the yaw drive. To design the accelerated life test of the yaw drive, this study reviewed the torque, lubrication condition, and frequency of use and etc. Finally, this selected the torque as the acceleration factor which is affected mainly to the system and also, the test equipment was developed based on the requirement of the life and performance test.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.9 no.2
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• pp.1-13
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• 2014

This study is preliminary founding start-ups of restaurant entrepreneurs to study the characteristics of management in order to provide useful information was studied. Survey period is from 2013 March 15 to August 31. About the nature of the preparation and establishment founder findings restaurant entrepreneurs of Western Gyeongnam area were most often in the form of an independent establishment has been compiled, work experience and other industries operating experience was more than restaurant entrepreneurs of operating experience. Hypothesis Testing in accordance with results of this study are as follows. First, the 50 founders than 30 founders quickly when the customer complaint or that service, order food and non-food note is issued after obtaining the order or that provide food, no customer is often inconvenient check the sharing services, such as personnel activities were devoting a lot of effort. Second, the re-startups restaurant entrepreneurs than new startups restaurant entrepreneurs was founded after the founder of career-related customer complaints about food more active coping was, and re-startups restaurant entrepreneurs by the founder other than business founded by the founder of the food-related customer complaints more aggressively for coping, respectively. Third, restaurant entrepreneurs of the store operations management has integrity, words and actions match, such as the degree of belief in the promise of reliability and the possibility of failure, which means the degree of recognition and response efforts are having an impact deal. Fourth, restaurant of food service management services and after-sales service has impact on the founder of the self-efficacy and self-efficacy of pre-service features and reliability founder affecting. Fifth, the revenue of the restaurant for dealing with customer complaints management includes efforts are having an impact. Sixth, restaurant founder of reliability and customer care has influenced the self-efficacy. Seventh, management of operational management activities have a positive impact on business performance are.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2001.10a
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• pp.7-10
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• 2001

The development of information communication technology leads the growth of logistic industry including delivery service as well as electronic commerce. The researchers predict that it will be still improving for the next several years. The logistic information system of railroad courier has been growing for a long time with small-package delivery transportation which is similar to the land-road delivery system. Despite of the long-time growth, it is recently in pain of the great loss since the 1990's, due to the failure to satisfy the customer's need for door-to-door delivery service. But the logistic information system of railroad still has the great potential. There are so many benefits such as timeliness, Punctuality, speed, multi-node storage base, transportation efficiency, energy frugality, environmental sociability, and so on. If the railroad logistic system plays a role of a portion of the nation-wide logistic with other logistic system, the synergy through the balancing logistic will also get much of international competitive advantages. So the objective of this research is to design the model and prototype of the web-based logistic system from which railroad service provider(Korean National Railroad), delivery service providers, and the customers can share the best effective delivery information.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.30 no.4
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• pp.45-56
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• 2022

Recently, the airport operator provides information such as real-time airport processing status, which allows users to determine the time to arrive at the airport at their own judgment. It is provided through their website and mobile Apps in order to resolve the customer's failure to board the aircraft and the inconvenience caused by waiting for the airport, etc. However, there was a lack of research cases on the intention of users to continue using such real-time airport information. Therefore, research on the field was studied by applying flow and trust theory based on human emotions. The research method verified reliability, validity, correlation between variables, and hypotheses using structural equations. As a result of the study, it was found that flow and trust had a significant effect on the intention to continue using. In other words, passengers were intended to continue to use the behavior they were searching for when they felt wise, enjoyable, and reliable etc.

• Journal of Information Technology Services
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• v.16 no.4
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• pp.33-46
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• 2017

Increasing popularity of smartphone is creating many changes in payment market sector also. The new fin-tech and simple mobile payment service have provided convenience as well as various benefits and value-added services to create new payment culture. However, the infrastructure of offline shops is too poor for users to use the simple mobile payment services in Korea. There are several reasons why the support of simple mobile payment services by offline shops has reached the limit in Korea. They include the reluctance of shop owners due to highly priced devices, the failure of NFC of the leading offline payment infrastructure to support iOS, the services that are biased to the specific manufacturers and smartphones (Samsung Pay and LG Pay), prefer large shops (SSG Pay and L PAY), and focus on online transactions. This study used the Bluetooth technology that is the standard feature built in all smartphone to expand the offline shops that accept the simple mobile payment services ensuring universality and scalability from the convenience of customer's and service provider's aspects. Applying the same payment scene as the existing NFC payment method from the user's aspect and the Bluetooth technology from the service provider's aspect enables support of all smartphones and offering value-added services such as electronic receipt and promotions through the large-capacity bidirectional data transfer. This study is intended to review the simple mobile payment services in Korea and other countries, propose the simple mobile payment service model for Korea by analyzing the Bluetooth technology and preceding studies of payment services using BLE technology, and develop the pilot system using the BLE technology to verify the proposed system with actual shops.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.12B
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• pp.1498-1508
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• 2011

A cloud service customer has no other way but to wait for his lost data to be recovered by the cloud service provider when the data was lost or not accessible for a while due to the provider's system failure, cracking attempt, malfunction, or outage. We consider a solution to address this problem that can be implemented in the cloud client's domain, rather than in the cloud service provider's domain. We propose a high level architecture and scheme for successfully retrieving data units even when several cloud storages are not accessible at the same time. The scheme is based on a clever way of partitioning and partial overlapping of data for being stored on multiple cloud storages. In addition to providing a high level of data availability, the scheme makes it possible to re-encrypt data units with new keys in a user transparent way, and can produce the complete log of every user's data units accessed, for assessing data disclosure, if needed.

• Journal of the Korean Data and Information Science Society
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• v.24 no.1
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• pp.85-94
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• 2013

As the financial market becomes larger, the loss increases due to the failure of the credit risk managements from the poor management of the customer information or poor decision-making. Thus, the credit risk management also becomes more important and it is essential to develop a credit scoring model, which is a fundamental tool used to minimize the credit risk. Credit scoring models have been studied and developed only for binary target variables. In this paper, we consider other types of target variables such as ordinal multinomial data or longitudinal binary data and suggest credit scoring models. We then apply our developed models to real data and random data, and investigate their performance through Kolmogorov-Smirnov statistic.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.18 no.5
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• pp.91-107
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• 2023

Lean startup is a concept that combines the words "lean," meaning an efficient way of running a business, and "startup," meaning a new business. It is often cited as a strategy for minimizing failure in early-stage businesses, especially in software-based startups. By scrutinizing the case of a startup L, this study suggests that lean startup methodology(LSM) can be useful for hardware and manufacturing companies and identifies ways for early startups to successfully implement LSM. To this end, the study explained the core of LSM including the concepts of hypothesis-driven approach, BML feedback loop, minimum viable product(MVP), and pivot. Five criteria to evaluate the successful implementation of LSM were derived from the core concepts and applied to evaluate the case of startup L . The early startup L pivoted its main business model from defecation alert system for patients with limited mobility to one for infants or toddlers, and finally to a smart bottle for infants. In developing the former two products, analyzed from LSM's perspective, company L neither established a specific customer value proposition for its startup idea and nor verified it through MVP experiment, thus failed to create a BML feedback loop. However, through two rounds of pivots, startup L discovered new target customers and customer needs, and was able to establish a successful business model by repeatedly experimenting with MVPs with minimal effort and time. In other words, Company L's case shows that it is essential to go through the customer-market validation stage at the beginning of the business, and that it should be done through an MVP method that does not waste the startup's time and resources. It also shows that it is necessary to abandon and pivot a product or service that customers do not want, even if it is technically superior and functionally complete. Lastly, the study proves that the lean startup methodology is not limited to the software industry, but can also be applied to technology-based hardware industry. The findings of this study can be used as guidelines and methodologies for early-stage companies to minimize failures and to accelerate the process of establishing a business model, scaling up, and going global.

• The Korean Journal of Nuclear Medicine Technology
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• v.12 no.1
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• pp.57-61
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• 2008

Purpose: $^{18}F$-FDG PET is to evaluate the tumor using glucose metabolism. Blood Glucose Level (BGL) is important factor that affects on a result of examination. But it often appears the distort result on diabetic patient due to a failure of BGL control. The aim of this study is to make a effective guideline for diabetic patient prescribed $^{18}F$-FDG PET and improve accuracy and reliability of examination. Materials and methods: A subject of study is 69 diabetic patients and divided them into 3 groups; 1) BGL is less than 120 mg/dl & performed PET, 2) BGL is over than 120 mg/dl & performed PET, 3) BGL is over than 120 mg/dl & not performed PET. And we investigated the type of diabetic medications and the time of dosage, whether they have meal or not. And we analyzed SUV of liver and mediastinum to recognize the effect of BGL on PET images. Results: As a methods to diabetic control, Amalyl showed high percentage of 27.5% in oral medication and Humulin R showed 14.5% in insulin. Their peak time was 2-3 hrs, 2-4 hrs and duration time was 24 hrs, 5-7 hrs. The number of that had a breakfast was 16, 7 mens (43.8%) couldn't perform PET as over 120 mg/dl and 5 mens (31.3%) performed PET as less than 120 mg/dl after they took a medication. When we set the SUV of normal for 1.5-2.0, 1.0-1.5 on liver and mediastinum, the percentage out of the range was 31.8%, 52.9%, 62.5% in 120-139 mg/dl, 140-159 mg/dl, 160-200 mg/dl respectively. Conclusions: We completed standardized guideline for diabetic patients. As a result of this study, improved customer satisfaction and increased economic benefits. It is expect to be a effective model in other PET centers.