• KIPS Transactions on Computer and Communication Systems
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• v.6 no.2
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• pp.75-86
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• 2017

Docker, which is one of the various virtualization technology in server systems, is getting popular as it provides more lightweight environment for service operation than existing virtualization technology. It supports easy way of establishment, update, and migration of server environment with the help of image and container concept. As the adoption of docker technology increases, the attack motive for the server for the distribution of docker images and the incident case of attacking docker-based hosts would also increase. Therefore, the method and procedure of digital forensic investigation of docker-based host including the way to extract the filesystem of containers when docker daemon is inactive are presented in this paper.

• Journal of the Korean Solar Energy Society
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• v.31 no.6
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• pp.23-31
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• 2011

The wind energy is one of the most prospective resources in renewable energy. However, the WTGS shouldn't be installed indiscriminately because the power system can be negatively influenced by a variable and uncertain nature of the wind energy. It is the reason why it has to be limited to install the WTGS thoughtlessly mentioned above that support the importance of the maximum penetration limit of wind power. It may required that power system operators suggests a new way of power system operation as percentage of the WTGS increase in the existing power system. The wind power is fixed in a limited area, so using rate of the wind power will be increased by installing additional WTGS. In this paper, we have studied on economic evaluation of the wind capacity increased by restricting the output of the WTGS as the way to increase the wind capacity.

• Industrial Engineering and Management Systems
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• v.11 no.3
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• pp.276-287
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• 2012

Determining storage locations of containers is an important issue for efficient operation of container terminals. This study assumes a storage yard with a horizontal layout in which blocks are laid out in parallel to the quay and trucks enter at the side of a block to deliver (receive) a container to (from) the yard crane. Various storage rules for determining storage locations of containers are introduced. Simulation studies are conducted for evaluating various rules. The following guidelines are derived from the result of our simulation study: when designing a block, consider a block configuration in which the longest gantry and the longest trolley travel times of rail-mounted gantry cranes (RMGCs) are similar; do not restrict the types of containers that can be stored in a storage area; if different roles are to be assigned to different storage areas, one possible way is to divide a bay into two areas so that some rows in the bay are allocated to inbound containers while the other rows in the same bay are allocated to outbound containers; reserve the space in bay unit for a high productivity of RMGCs but reserve the space in stack unit when the storage space is not enough; when the storage space is not sufficient, allocate storage location in a way of starting from the end and ending at the middle of a block; for reducing the travel distance of internal trucks, provide a higher priority to a block nearer to the berthing position of the corresponding vessel.

• Journal of Internet Computing and Services
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• v.15 no.2
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• pp.49-58
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• 2014

With the fast development of internet, cloud computing has become the most demanded technology used all over the world. Cloud computing facilitates its consumers by providing virtual resources via internet. One of the prominent services offered in cloud computing is cloud storage. The rapid growth of cloud computing also increases severe security concerns to cloud storage. In this paper, we propose a scheme which allows users not only securely store and access data in the cloud, but also share data with multiple users in a secured way via unsecured internet. We use ECC for cryptography and authentication operation which makes the scheme work in a more efficient way.

• International Journal of Internet, Broadcasting and Communication
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• v.13 no.2
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• pp.60-66
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• 2021

Blockchain is a technology that enables trust-based consensus and verification based on a decentralized network. Distributed ID (DID) is based on a decentralized structure, and users have the right to manage their own ID. Recently, interest in self-sovereign identity authentication is increasing. In this paper, as a method for transparent and safe sovereignty management of data, among data pseudonymization techniques for blockchain use, various methods for data encryption processing are examined. The public key technique (homomorphic encryption) has high flexibility and security because different algorithms are applied to the entire sentence for encryption and decryption. As a result, the computational efficiency decreases. The hash function method (MD5) can maintain flexibility and is higher than the security-related two-way encryption method, but there is a threat of collision. Zero-knowledge proof is based on public key encryption based on a mutual proof method, and complex formulas are applied to processes such as personal identification, key distribution, and digital signature. It requires consensus and verification process, so the operation efficiency is lowered to the level of O (log_eN) ~ O(N²). In this paper, data encryption processing for blockchain DID, based on zero-knowledge proof, was proposed and a one-way encryption method considering data use range and frequency of use was proposed. Based on the content presented in the thesis, it is possible to process corrected zero-knowledge proof and to process data efficiently.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.20 no.2
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• pp.137-146
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• 2013

Purpose: The purposes of this study were to identify and compare various types of post operative pain management and the costs for pain management following 4 different types of surgery. Methods: Data were collected from 325 medical charts which were extracted from the billing databases of a tertiary hospital and analyzed using numbers, percentages, one way ANOVA, and Scheff$\acute{e}$ test. Results: For pain management, 10.5% of patients used PCA only, but the other patients combined other methods with PCA. The average length of PCA use was significantly different by operation. Almost one third (32.9%) of patients experienced at least one of side effects due to analgesics used for pain management, with highest incidence being for nausea and vomiting. For patients who underwent a total abdominal hysterectomy, 34.7% used PCA less than 2 days due to side effects of the analgesics and the ratio of analgesia cost to total hospital cost and total pharmacy cost were highest compared to other operations. Conclusion: The results of this study indicate a need to develop new strategies to more effectively manage postoperative pain to decrease incidences of side effects without increasing medical costs.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.2
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• pp.172-177
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• 2009

Most of the causes of the failures of power transformers in operations are mechanical defects due to vibration. To identify these causes, the vibration phenomenon was measured from the power transformers in operation in the substations under the Daejeon power transmission district office of KEPCO. The measurement was performed in a 6${times}$4 structure on one side of the transformer. The vibration of the measured points was presented in 2D and 3D, and analyzed. The results according to the period in use of the transformer and the load applied to the transformer were analyzed. These results will be used as basic data to establish the vibration standard for the power transformer, In addition, with a load capability and vibration phenomenon correlation and regression analysis to identify by way of function was reached. And the vibration phenomenon pass a years with changes and to analyze correlation, was estimated to bring in the function. And then through the analysis of power transformers to set standards based on vibration data was used to.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.11
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• pp.705-710
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• 2011

Fault detection has to be proceeded by steady state filtering to get rid of transient effect associated with thermal capacity. Coefficient of variance (COV), ratio of standard deviation devided by moving average, was employed as steady-state filter. Engine speed and refrigerant pressures were selected as parameters representing system dynamics. The filtered values were registered as members of steady-state DB. They were found to show good functional relationship with ambient temperature. The relationship was fitted with a second order polynomial and the distribution bounds of the data around the fitted curve were expressed by visual inspection because of varying average and random data interval. Fault data were compared with the steady-state data obtained during normal operation. The fault data were easily isolated from the fault-free one. To make such isolation reliable, tests to construct good DB should be designed in a systematic way.

• Journal of the Korean Dietetic Association
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• v.12 no.3
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• pp.235-242
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• 2006

The purpose of this study of was to provide basic data for preparing event menus to increase customer's satisfaction by investigating university students' participation and preference for the event menus in the foodservice operations. The questionnaires were distributed to 300 customers from August 1 to 31, 2005. 88.0% of the questionnaires were analyzed. Statistical analysis of data was performed using SAS package program(version 8.2) for descriptive analysis and $χ^2$-test, t-test, one-way ANOVA, Duncan multiple range test. The results of this study can be summarized as follows : 50.4% of the students have participated in foodservice operation's event and the average degree of the satisfaction was 2.67 out of 5. The type of the events customers have most frequently participated in were the national holiday·subdivisions of the season event(47.3%), the day event(34.1%), environment event(26.9%) and so on. In large classification, preferred were season event(85.2%), international food event(76.9%), and healthy food event(73.1%) and so on. In small classification, orgarnic food event(53.0%), summer fruits festival(41.3%), midsummer event(36.6%) and christmas event(34.4%) and so on. From now on, the event reflecting customers' expectation and requirement should be planned and implemented.

• Journal of ILASS-Korea
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• v.19 no.2
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• pp.55-63
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• 2014

Pyrolysis oil (PO), also known as Bio crude oil (BCO), has the potential to displace significant amounts of fuels that are currently derived from petroleum sources. PO has been regarded as an alternative fuel for petroleum fuels to be used in diesel engine. However, the use of PO in a diesel engine requires modifications due to low energy density, high water contents, low acidity, and high viscosity of the PO. One of the easiest way to adopt PO to diesel engine without modifications is emulsification of PO with the fuels that has higher cetane number. However, PO that has high amount of polar chemicals is immiscible with non polar hydrocarbons of diesel. Thus, to stabilize a homogeneous phase of diesel-PO blends, a proper surfactant should be used. In this study, a DI diesel engine operated with diesel and diesel-PO emulsions was experimentally investigated. Performance and gaseous & particle emission characteristics of a diesel engine fuelled by diesel-PO emulsions were examined. Results showed that stable engine operation was possible with the emulsions and engine output power was comparable to diesel operation.