• Microbiology and Biotechnology Letters
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• 제31권3호
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• pp.250-256
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• 2003

Lactic acid bacteria with amylolytic and acid producing activities can ferment starch directly to lactic acid thereby producing a monomer for the production of biodegradable poly lactic acid (PLA). In this study, the strain producing L-lactic acid from soluble starch was isolated from Nuruk. The isolated strain was identified as Enterococcus sp. through its morphological, cultural, biochemical characteristics as well as the 16S rDNA sequence analysis, and named Enterococcus sp. JA-27. Enterococcus sp. JA-27 produced exclusively L-lactic acid from soluble starch as a carbon source. The optimal conditions for the maximum production of L-lactic acid from Enterococcus sp. JA-27 were 30 C, pH 8, 1.5 % soluble starch as a substrate and 3.5 % tryptone as a nitrogen source, 0.1 % $K_2$$HPO_4$, 0.04 % $MgSO_4$. $7H_2$O, 0.014 % $MnSO_4$$.$4$H_2O$, 0.004% $FeSO_4$$.$$7H_2$O. Batch and fed batch culture were carried out and the former was more effective. L-Lactic acid production in the optimum medium was significantly increased in a 7 L jar fermenter, where the maximum L-lactic acid concentration was 3 g/L. For the purification of lactic acid in fermented broth, two stage ionexchange column chromatographies were employed and finally identified by HPLC.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제21권2호
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• pp.366-372
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• 2020

The Army's rocket missile is a one-shot weapon system, which is produced and used for only one mission, and requires high reliability. While reliability analysis with failure data can result in underestimation of the life distribution, reliability analysis with all the non-failure data can result in overestimation of the life distribution. Under or overestimation of the life distribution can lead to cost increase by early disposal or complete observation of all rocket missiles. In order to overcome this problem, the Army suggests the guideline of the number of samples from non-failure data for reliability analysis with failure data. However, the currently used sampling method can generate errors for predicting the failure rate. To solve this problem, this study proposes a new sampling procedure for predicting a future failure rate using non-failure data. The comparison test between the currently used sampling method and the proposed sampling method is conducted and the result shows that the proposed sampling method can predict the future failure rate more accurately.

• The Journal of the Korea Contents Association
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• 제4권1호
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• pp.55-66
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• 2004

Recently, as the personal computers are supplied rapidly, they formed the nucleus of the computer system. But, because of the easiness that anyone uses them to go near easily, it is the fact that the security of personal computer is weakness. So, in the paper, 1 propose the technical method that minimizes the loss and leakage of important data. This paper implemented a crypto system for security of data file on personal computer and assistance storage medium. The way of encryption/decryption is applied by complexity method which mixed Diffie-Hellman key exchange protocol, a typical RC4(Rivest Cipher version 4) algorithm of stream cipher and a typical MD5(Message Digest version 5) of Hash Function. For valuation implemented crypto system, three criteria is presented, which are crypto complexity, processing time and pattern matching. And according to analysis the three criteria the crypto system is verified the security, efficiency and usefulness. The crypto system is programmed with Visual C++ language of Microsoft. And so, as this is software system, we shall have a technical security system at a minimum cost for all personal computer.

• Journal of Korean Society of Transportation
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• 제30권3호
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• pp.95-106
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• 2012

The railway service in the Seoul metropolitan area is facing variety of l changes such as extension of service coverage, new construction, and introduction of express service which in turn causes changes on demands. The demand affects train operation characteristics (frequency of service, train formation) as well as on the congestion rate which is one of the major evaluation index in metropolitan area user service. For the efficient operation of the train, the relationship among the minimization of fleet number, operating cost, and service level has been analyzed. Using the Powersim, which is a system dynamics (System Dynamics) simulation program for realizing optimized simulation for train-formation, this paper identified that some stations of Gyeong-bu line exceeded limit congestion rate(150%) of a fleet already that means it is best to maintain current condition of the line; however, the Gyeong-in line and the Gwa-chon line showed no excess of the limit congestion rate so that it is possible to reduce 2-4 fleets of train for efficient operation. In addition, in case of Jang-hang line between Cheon-an and Sin-chang, a train consisting of 10 fleets provides services which is same formation of train for Gyeong-bu line. This study proved that the congestion rate will not rise greatly with only 4 fleets of a train for the service in Jang-hang line, and it is considered that a study for shuttle service between Cheon-an and Sin-chang is necessary.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제7권3호
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• pp.461-467
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• 2003

This paper proposes the method of mobility implementation for location searching in the intelligence wireless ATM networks that expand and apply standard broadband signaling capabilities, and analyze the performance based on the numerical algorithm. The existing B-ISDN UNI protocol stack demands the location search mechanism to determine the location of mobile terminal in the wireless ATM networks because it use single protocol through the fixed PTP interface or PTM interface that don't support terminal mobility. The proposed method make possible the dynamic mobility at a part of wireless access by minimizing the signaling load without a falling-off in system performance by using the intelligence network technology according to the expansion of ATM and B-ISDN signaling integration based on the fixed networks. We implemented the performance analysis by MFC modeling based on numerical algorithm, and realized the efficiency of expenses by carrying out the comparative signaling performance evaluation to measure the relative gains of location search service in the intelligence wireless ATM system. The obtained results have the flexibility to operate in the public B-ISDN network environment without a change of existing B-ISDN/ATM NNI signaling reference to support the wireless ATM access system, and can easily expand to correspond to terminal mobility and various multimedia services in the next broadband PCS.

• Journal of Korea Water Resources Association
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• 제42권7호
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• pp.537-546
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• 2009

Determination of optimal pressure monitoring location is essential to manage water distribution system efficiently and safely. In this study, entropy theory is applied to overcome defects of previous researches about determining the optimal sensor location. The previous studies required the calibration using historical data, therefore, it was difficult to apply the proposed method in the place where the enough data were not available. Also, most researches have focused on the locations to minimize cost and maximize accuracy of the model, which is not appropriate for the purpose of maintenance of the water distribution system. The proposed method in this study quantify the entropy which is defined as the amount of information calculated from the pressure change due to the variation of discharge. When abnormal condition is occurred in a node, the effect on the entire network is presented by the entropy, and the emitter is used to reproduce actual pressure change pattern in EPANET. The optimal location to install pressure sensors in water distribution system is the nodes having the maximum information from other nodes. The looped and branched networks are evaluated using the proposed model. As a result, entropy theory provides general guideline to select the locations to install pressure sensors and the results can be used to help decision makers.

• The Journal of Korean Society for Radiation Therapy
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• 제17권1호
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• pp.45-55
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• 2005

Purpose : To evaluate the usefulness of the handmade patient immobilization device and to report the clinical results of it. Materials and methods : We made two fusion images and analyzed those images. One image is made with diagnostic MR image and CT image, the other with therapeutic planning MR image and CT image. With open head holder, we measured the skin dose and attenuation dose. Also, we made the planning CT couch plate with acrylic plate and styrofoam and compared artifact. Results : We could get more accurate fusion image when we use MR head holder(within 2mm error). The skin dose was reduced 2 times and the attenuation dose was reduced more than $20\%$ when open head holder used. The planning CT couch plate was more convenient than conventional board and reduced artifact remarkably. Conclusion : We could verify the localization point in the MR image which is taken with MR head holder. So we could fuse the image more accurately. The same method could be applied to PET and US image, if the alike immobilization device used. With open head holder, the skin dose and the attenuation dose was reduced. And those above devices could substitute for expensive foreign device, if those are manufactured adequately.

• Journal of Internet Computing and Services
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• 제19권1호
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• pp.87-95
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• 2018

Due to global warming and increased energy costs around the world, interests of energy saving and efficiency have been increased. In particular, forging factories need methods to save energy and increase productivity because of needing amounts of energy uses. To solve the problem, we propose a system, which includes collection, monitoring, and analysis process, to monitor energy uses each facility in realtime based on the IoT devices. This system insists of worksheets management, facility/energy management, realtime monitoring, history search, data analysis through connecting with existed ERP/MES Systems in manufacturing factories. The energy monitoring process is to present used energy collected from IoT devices connected with installed gasmeter and wattmeter each facility. This system provide the change of energy uses, usage fee, energy conversion, and green gas information in realtime on Web and mobile devices. This system will be enhanced with energy saving technology by analyzing constructed big data of energy uses. We can also propose a method to increase productivity by integrating this system with functions of digitalized worksheets and optimized models for production process.

• Journal of Oral Medicine and Pain
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• 제38권1호
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• pp.29-34
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• 2013

Objective: All patients who have the disc displacement with reduction (DDwR) are always not progressive but some of them with significant catching or locking progress to disc displacement without reduction (DDw/oR). In this study, we suggest opening exercise therapy using Locking-free Appliance (LA) to be helpful to prevent progressive derangement. Methods: Retrospectively, a total 37 patients who received exercise treatment using LA was analyzed from January 2010 to December 2011. Patients had been instructed in proper exercise technique to practise for opening and closing of mouth wearing the appliance 30 times a day in locking-free position. Results: None of the patients took a turn for worse to DDw/oR (37 patients). The 16 patients (43.2%, locking-free group) of them could open their mouth without intermittent condylar locking. Measurement of data was analyzed using and Mann-Whitney test. There was no statistically significant difference for age, gender, presence of palpational pain, locking period, VAS quantitative pain score between locking-free group and locking group. Conclusions: In this study, some patients could open their mouth without intermittent locking and did not take a turn for worse to DDw/oR after opening exercise therapy with LA. Furthermore, LA had advantages which were short wearing time, low costs and minimizing patients' uncomfortable compared to conventional treatment method. This therapy can be more appropriate new treatment to prevent progress to DDw/oR.

• Journal of Service Research and Studies
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• 제9권4호
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• pp.63-80
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• 2019

This study presents strategic implications for enhancing the competitiveness of the comprehensive health examination center through the study of its impact on the switching barrier with medical service value and medical service satisfaction as parameters. In order to achieve the purpose of this study, a total of 324 questionnaires were analyzed for customers who received health examinations at the general examination center. Covariance structure analysis was performed to test hypotheses and causal relationships. The results showed that the physical environment had a significant effect on the medical service value and medical service satisfaction. The value of medical service also had a significant effect on medical service satisfaction. The value of medical service was found to affect the transition barrier, but the satisfaction of medical service did not affect the transition barrier. The implications of this study are that physical environment has a significant effect on medical service value and medical service satisfaction. Therefore, modern medical equipment should be equipped with the latest medical equipment to minimize accurate examination and misdiagnosis through modernization of medical examination center. In addition, since the value of medical service has a significant effect on the switching barrier, it is necessary to establish a plan to enhance the value of medical service. We need to promote sustainable customer retention and creation of new customers through differentiated screening items and cost advantages over competitors. In addition to check-up services, efforts should be made to enhance the value of services such as strengthening medical communication and medical complex cultural spaces, and at the same time, establish an organizational culture of customer-first examination centers through the placement of excellent personnel and continuous education.