• Korean Management Science Review
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• v.11 no.1
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• pp.145-163
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• 1994

For an Information System to be successful the continual control of the database system(DBS) is very important. In general, such control operations are performed periodically in batches, even in real time systems. We explain DBS related such control operations and describe the decision problem in each of them. Specifically, backup, checkpointing, reorganization, and batch update operations are considered. Then we develop a general model of the batch backup situation to determine the optimal backup timing. Other operations are considered as special cases of the general batch backup operation are derived and compared. We show that, in general, the control limit policy is superior to the fixed time interval policy in terms of the long-run average cost per unit time. Some practical considerations about the implementation of optimal policies are also mentioned.

• Journal of Korean Foot and Ankle Society
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• v.6 no.2
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• pp.211-216
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• 2002

Delay in diagnosis is possible in bone tumor located in the foot because it is rare. We experienced one case of osteoid osteoma located at the navicular bone of the foot which was slowly progressive and complicated with calcaneocuboidal joint, talonavicular joint arthritis. Osteoid osteoma of the navicular bone in the foot is rare. It bring about unwanted delay in diagnosis, complication. It is necessary to diagnose and treat in early situation to prevent complication and unnecessary operation.

• Proceedings of the Ginseng society Conference
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• 1990.06a
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• pp.190-195
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• 1990

• Journal of Ginseng Research
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• v.14 no.2
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• pp.332-337
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• 1990

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.12
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• pp.8568-8575
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• 2015

This study, as a experiment study, was intended to determine whether or not the situational leadership program was highly helpful to critical thinking, coaching, empowerment-enhancing of nurse managers. The number of subjects was abstracted by G*Power, and 54 nurses leader and 342 general nurses were selected from university hospitals of metropolitan city. Data analysis was frequency analysis, t-test, $X^2$-test, repeated measures ANOVA, using SPSS Win 18.0 statistical package program. The results of this study was as follows. 1. Due to the situation leadership programs, critical thinking of experiment group has significantly increased, but control group was significantly reduced. 2. Due to the situation leadership programs, coaching of experiment group has significantly increased, but control group was significantly reduced. 3. Due to the situation leadership programs, empowerment of experiment group has significantly increased, but control group was significantly reduced. Therefore, the situation leadership programs can be effective in critical thinking, coaching, empowerment of nurse leaders. And applying the situation leadership program to the nurse in future, it would be helpful promoting empowerment, coaching, critical thinking in organization life and cope with situation that occurred during clinical.

• The KIPS Transactions:PartB
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• v.8B no.6
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• pp.669-674
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• 2001

In order to reflect the aggregation situation in the aggregation process, aggregation based on situation assessment (ASA) method was proposed in [1]. It consists of the situation assessment model (SAM) and the ASA algorithm. In the SAM, the value of parameter, p, is transformed into the nearest integer value [1]. The integer-typed output of SAM is used as input for an aggregation. The integer-typed output of SAM indicates the current degree of aggregation situation. The ASA algorithm produces at most finite several aggregation results between min and max. In the sequel, the ASA method can not properly handle the applications with the more sophisticated aggregation results between min and max. In order to solve this problem, we propose two improved ASA (I-ASA) methods. In these I-ASA methods, we allow the value of parameter of SAM to be a real number, and suggest two improved ASA algorithms to make continuous aggregation results between min and max. These I-ASA methods can handle both a precise aggregation and an approximate aggregation. Therefore, when compared to the ASA method [1], the proposed I-ASA methods have advantages in that they can handle the applications with the more sophisticated aggregation results and can be used in the more general applications for aggregations.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.6
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• pp.406-412
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• 2023

In this paper, we studied the effect of noise caused by ambient light on a reflective PPG measurement device using infrared light. Noise caused by ambient light was examined by dividing it into general situations and special situations. In the general situation, noise due to changes in time and ambient light sources was randomly observed, and in the special situation, a halogen lamp was used to observe the effect of noise variations. In the experiment, PPG signals were measured and data acquired in real-time depending on each situation, and the measured data was analyzed in the time domain and frequency domain. First, through a general situation experiments, it was visually observed that noise increases with the brightness of ambient light, and through frequency analysis, it was observed that the noise sources were white noise, power line noise, and internal noise of the circuit. Futhermore, using a halogen lamp, we experimented with the change in noise depending on the change in distance from the ambient light and calculated the SNR. As a result of the experiment, an SNR of 3.2 dB was shown at a distance of 50 cm with an irradiance of 278.3 W/m². It was observed that normal measurement was difficult at SNRs below that, and an irradiance of 27.7 W/m² was obtained. It showed a value of 18.2 dB at a distance of 2 m, and it was observed that normal PPG measurement was possible through a filter at values above that.

• Journal of the Korea Society of Computer and Information
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• v.27 no.1
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• pp.61-67
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• 2022

In this paper, we propose a model that can convert some of the simulation program resources to a mobile environment. Recently, smart factories that use PLCs as controllers in the manufacturing industry are rapidly becoming widespread. However, in the situation where it is difficult to operate due to the shortage of PLC operation personnel, the actual situation is that a platform for PLC operation education is necessary. Currently most PLC-related educational platforms are based on 2D, which makes accurate learning difficult and difficult. When a simulation program is applied to distance learning in a general PC environment, many elements are displayed on the monitor, which makes screen switching inconvenient. Experiments with the proposed model confirmed that there was no frame deterioration under general circumstances. The average response time by the request frame was 102 ms, and it was judged that the learner was not at the level of experiencing the system delay.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.906-909
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• 2007

The method of distributing some questionnaires to the total 4 schools in the area of Gwang-ju city and then collect them later has been used in this study. By using the coefficient of Cronbach's alpha for the collected data, the trust rate of the method of questionnaires have been verified. In conclusion it's been analized that there are disparities in 'computer education course, professor lesson, possibility of computer use, teaching obstacles, self development of teachers, choice and organization of the computer education contents' according to the general situation of the teachers who charge computer education sand there are also disparities in 'goal of computer education, computer curriculum related learning activity, computer curriculum related learning satisfaction, practical use of computer facility, interested contents of students, other lessons besides regular education course' according to the general situation of the students who receive computer education in commercial high school.

• The Journal of the Korea Contents Association
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• v.21 no.12
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• pp.190-201
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• 2021

The variable message sign (VMS) is equipment to improve the efficiency of traffic flow and safety of travel by providing real-time information to road users on traffic, road, weather situation, and traffic control due to construction. The information messages of the letter-based VMS taking up most of the VMS on the general national highways consist of section, travel time in sections, and road control situation. This study devised an improvement plan centered on road users, not road managers-centered existing message-based VMS through an analysis of road users' preference targeting the letter-based VMS operated in the general national highways in the Seoul Metropolitan Area. By presenting the measure for system improvement through which information on unexpected situations that road users prefer the most can be quickly and efficiently provided, this study aims to improve the efficiency of road user-centered VMS traffic information.