• Journal of the Korea Society of Computer and Information
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• v.24 no.4
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• pp.65-71
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• 2019

IAs smart device penetration rate is more than 90%, mobile transaction ratio using smart device is increasing. Smart contracts are used in various areas of real life including smart trading. By applying smart contracts to the platform for smart transactions through block-chain technology, the threat of hacking or forgery can be reduced. However, various threats to devices in smart transactions can pose a threat to the use of block chain Etherium, an important element in privilege and personal information management. Smart contract used in block chain Ethereum includes important information or transaction details of users. Therefore, in case of an attack of privilege elevation, it is very likely to exploit transaction details or forge or tamper with personal information inquiry. In this paper, we propose a detection and countermeasure method for privilege escalation attack, which is especially important for block chain for secure smart transaction using block chain Ethereum. When comparing the results of this study with the results of similar applications and researches, we showed about 12~13% improvement in performance and suggested the future countermeasures through packet analysis.

• International Journal of Naval Architecture and Ocean Engineering
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• v.11 no.1
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• pp.474-481
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• 2019

The speed trial of a ship is one of the important elements guaranteeing its performance under the contract between the ship owner and shipbuilding company. A speed trial at sea, where the tidal current and waves are suppressed to the maximum, can prevent measurement errors due to external force conditions. On the other hand, it is difficult to maintain a calm sea state in most sea areas determined by the influence of the tidal current, wave, wind, etc. Therefore, this study evaluated a method of simulating a tidal current, which is one of the external force conditions, at the speed test operation of a ship, and applied the simulation result to the plan of a speed trial.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.16 no.1
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• pp.72-80
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• 2016

Re-auction happens when a bid winner defaults on the payment without making second in-line purchase declaration even after determining sales permission. This is a process of selling under the court's authority. Re-auctioning contract price of real estate is largely influenced by the real estate business, real estate value, and the number of bidders. This paper is designed to establish a statistical model that deals with the number of bidders participating especially in apartment re-auctioning. For these, diverse factors are taken into consideration, including ratio of minimum sales value from the point of selling to re-auctioning, number of bidders at the time of selling, investment value of the real estate, and so forth. As an attempt to consider ambiguous and vague factors, this paper presents a comparatively vague concept of real estate and bidders as trapezoid fuzzy number. Two different methods based on the least squares estimation are applied to fuzzy regression model in this paper. The first method is the estimating method applying substitution after obtaining the estimators of regression coefficients, and the other method is to estimate directly from the estimating procedure without substitution. These methods are provided in application for re-auction data, and appropriate performance measure is also provided to compare the accuracies.

• Korea Journal of Hospital Management
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• v.13 no.4
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• pp.119-145
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• 2008

The objectives of this study were to inspect how the law effected on hospital employment system and which policy and strategy are needed to cope with the present situation as the law regarding irregular workers law has enacted for a year. To grasp the changes of employment style in hospital, 56 hospitals among 311 general hospitals were questioned in this study. And employment policy and strategy were developed by referencing examples of developed nations and other industries. The survey showed that the wage and welfare level of irregular workers in hospitals was improved compared to that in the other industries. But there were still much discrimination between regular and irregular workers. The policy direction of government is, first of all, to follow the principle of equal treatment to equal value of labour. The first feasible policy is to enforce social security. The second one is an employment promotion policy which reduces or exempts hospitals employing irregular workers from tax and insurance fee. The third one is to extend employment contract period to 3 years. and finally there are policies to permit more dispatched jobs and to expand the social insurance coverage. The strategies to solve the problem of irregular workers are as follows; 1) performance wage system, 2) guaranteeing employment by unlimited contract, 3) creating new category of workers, 4) the wage system of management by object, 5) the method of job classification. This study has a meaning in the point that it was studied on hospital which is special industrial part and analyzed the changes after enacting irregular workers law and presented management strategy for countermeaure program. In this study, it was expected to contribute to decisions-making in hospital management, especially when using human resources.

• Korean Journal of Construction Engineering and Management
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• v.22 no.5
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• pp.66-72
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• 2021

Participation in official development assistance (ODA) construction projects can be proposed as a way to revitalize Korean small and medium-sized construction companies' entry into the overseas construction market. To this end, the necessary competency items were derived for the execution of the project, and a survey was conducted and an analysis of importance-current competency was performed. 24 out of a total of 32 competency items were analyzed as having a low level of competency compared to their importance, indicating that it is urgent to strengthen corporate-level capabilities for the smooth execution of related projects in the future. In detail, it is judged that it is necessary to seek to establish a preferential capacity-strengthening plan for contract management-related items such as the 'Construction-related fundamental laws, Contract management method, and International administration negotiation'.

• Journal of Intelligence and Information Systems
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• v.25 no.2
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• pp.77-97
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• 2019

The large amount of data that emerges from the initial connection environment of the Fourth Industrial Revolution is a major factor that distinguishes the Fourth Industrial Revolution from the existing production environment. This environment has two-sided features that allow it to produce data while using it. And the data produced so produces another value. Due to the massive scale of data, future information systems need to process more data in terms of quantities than existing information systems. In addition, in terms of quality, only a large amount of data, Ability is required. In a small-scale information system, it is possible for a person to accurately understand the system and obtain the necessary information, but in a variety of complex systems where it is difficult to understand the system accurately, it becomes increasingly difficult to acquire the desired information. In other words, more accurate processing of large amounts of data has become a basic condition for future information systems. This problem related to the efficient performance of the information system can be solved by building a semantic web which enables various information processing by expressing the collected data as an ontology that can be understood by not only people but also computers. For example, as in most other organizations, IT has been introduced in the military, and most of the work has been done through information systems. Currently, most of the work is done through information systems. As existing systems contain increasingly large amounts of data, efforts are needed to make the system easier to use through its data utilization. An ontology-based system has a large data semantic network through connection with other systems, and has a wide range of databases that can be utilized, and has the advantage of searching more precisely and quickly through relationships between predefined concepts. In this paper, we propose a defense ontology as a method for effective data management and decision support. In order to judge the applicability and effectiveness of the actual system, we reconstructed the existing air force munitions situation management system as an ontology based system. It is a system constructed to strengthen management and control of logistics situation of commanders and practitioners by providing real - time information on maintenance and distribution situation as it becomes difficult to use complicated logistics information system with large amount of data. Although it is a method to take pre-specified necessary information from the existing logistics system and display it as a web page, it is also difficult to confirm this system except for a few specified items in advance, and it is also time-consuming to extend the additional function if necessary And it is a system composed of category type without search function. Therefore, it has a disadvantage that it can be easily utilized only when the system is well known as in the existing system. The ontology-based logistics situation management system is designed to provide the intuitive visualization of the complex information of the existing logistics information system through the ontology. In order to construct the logistics situation management system through the ontology, And the useful functions such as performance - based logistics support contract management and component dictionary are further identified and included in the ontology. In order to confirm whether the constructed ontology can be used for decision support, it is necessary to implement a meaningful analysis function such as calculation of the utilization rate of the aircraft, inquiry about performance-based military contract. Especially, in contrast to building ontology database in ontology study in the past, in this study, time series data which change value according to time such as the state of aircraft by date are constructed by ontology, and through the constructed ontology, It is confirmed that it is possible to calculate the utilization rate based on various criteria as well as the computable utilization rate. In addition, the data related to performance-based logistics contracts introduced as a new maintenance method of aircraft and other munitions can be inquired into various contents, and it is easy to calculate performance indexes used in performance-based logistics contract through reasoning and functions. Of course, we propose a new performance index that complements the limitations of the currently applied performance indicators, and calculate it through the ontology, confirming the possibility of using the constructed ontology. Finally, it is possible to calculate the failure rate or reliability of each component, including MTBF data of the selected fault-tolerant item based on the actual part consumption performance. The reliability of the mission and the reliability of the system are calculated. In order to confirm the usability of the constructed ontology-based logistics situation management system, the proposed system through the Technology Acceptance Model (TAM), which is a representative model for measuring the acceptability of the technology, is more useful and convenient than the existing system.

• Journal of the Korean Dietetic Association
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• v.24 no.1
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• pp.1-18
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• 2018

Sustainable practices of school foodservices are gaining more attentions. The study aimed to investigate dietitians' performance levels of sustainable practices in school foodservice settings in Gyeonggi Provinces. Using a survey method was used, and data were collected from 358 participants (response rate 59.7%) to be analyzed using the SPSS program. The evaluation tool for sustainable practices of school foodservices consisted of four sections and 34 criteria with 100 points. Employment status of the respondents was as follows: nutrition teachers 40.9%, dietitians (permanent) 45.1%, and temporary position dietitians 13.2%. Dietitians' performance for sustainable practices marked 65.67 points out of 100 (performance rate 66%) and were in the following order by section: sustainable foodservice management criteria (69%), support activities (69%), planning and evaluation (68%), and outcome management (52%). Regarding sub-sections, criteria that acquired higher performance rates were labelling of food origin (99%), use of seasonal vegetables and fruits (98%), food waste management by contract dealer (98%), and planning for reducing of food waste and solid waste (91%). Meanwhile, criteria that showed the lowest scores were installing water conservation devices on equipment (19%), operating food donation programs for communities (21%), use of sensor lights for electricity conservation (24%), planning for annual energy conservation (40%), and implementation of education programs for foodservice workers on sustainable activities (42%). Performance scores differed according to school levels and working experience of dietitians, indicating that dietitians at elementary school foodservices or with work experience of 15 to 20 years showed higher performance than those at high schools or with less than 5 years of work experience (P<0.001, P<0.05). Based on the results, action plans for improvement were suggested.

• Journal of Energy Engineering
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• v.22 no.2
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• pp.90-95
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• 2013

The paper is aimed at evaluation method for technology-focused professional ESCO. We set up some premise about the evaluation indicators, there are such as the financial soundness, energy savings performance excellence, customer satisfaction, source technology vendor's participation, and guaranteed savings contract. The evaluation indicators consist of the evaluation of expertise (40points), management state (15points), customer satisfaction (20points), technical skills (25points), and detailed indicators were determined. We can apply technology categories such as lighting, cogeneration, process improvement, waste heat recovery, cooling & heating equipments.

• International conference on construction engineering and project management
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• 2007.03a
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• pp.30-40
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• 2007

The demand for light-rail construction projects has recently been increasing, and they are mostly supervised by private construction companies. Therefore, a private construction company that aim to raise gains from the operation of the facilities during the contract period greater than what they invested should b able to accurately calculate the costs from the aspect of Life Cycle Cost (LCC). In particular, a light-rail transit bridge that has a heavier portion from the aspect of the cost of light-rail transit construction requires a more accurate calculation method than the conventional LCC calculation method. For this, an LCC analysis model was developed and a cost breakdown structure was suggested based on literature review. The construction costs by shape of the upper part of a light-rail transit were calculated based on the cost breakdown system presented in this paper, and the cost generation cycle and cost unit price were collected and analyzed based on records on maintenance costs, rehabilitation and replacement. In addition, after forming some hypotheses in order to perform the LCC analysis, economic evaluation was conducted from the aspect of the LCC by using performance data by item.

• Journal of Digital Convergence
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• v.18 no.10
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• pp.253-263
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• 2020

Since the birth of the Ethereum in 2015, various decentralized applications (DApp) based on blockchain smart contract technology have appeared. However, CryptoKitty's case showed instability in terms of performance and scalability in real-world service environments. To solve this, a blockchain platform that developed a high transaction per second (TPS) has appeared, but there have been no environments and services to test it. Therefore, this paper intends to design and develop a game that can record the contents of all games on the chain and verify the performance and scalability of the blockchain platform through oversized transactions. The developed game generated a total of 6.3 million blocks and 8.9 million transactions through by 682 and verified the improved performance and scalability of the existing platform. Additionally, the maximum TPS was measured at 1,309 during the test period. In the future, it is expected that performance and scalability can be compared in a realistic environment through the method presented in this paper.