• Journal of the Korean Operations Research and Management Science Society
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• v.32 no.4
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• pp.89-99
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• 2007

In this paper, an analytic model of a sleep mode operation in the IEEE 802.16e is investigated. A mobile subscriber station(MSS) goes to sleep mode after negotiations with the base station(BS) and wakes up periodically for a short interval to check whether there is downlink traffic to it. If the arrival of traffic is notified, an MSS returns to wake mode. Otherwise, it again enters increased sleep interval which is double as the previous one. In order to consider the situation more practically, we propose the sleep mode starting threshold, during which MSS should await packets before it enters the sleep mode. By modifying the M/G/l with multiple vacations model, energy consumption ratio(ECR) and average packet response time are calculated. Our analytic model provides potential guidance in determining the optimal parameters values such as sleep mode starting threshold, minimal sleep and maximal sleep window.

• Journal of Information Technology Applications and Management
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• v.14 no.3
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• pp.95-113
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• 2007

To minimize IT operational risks and the opportunity cost for lost business hours. it is necessary to have preparedness in advance and mitigation activities for minimization of a loss due to the business discontinuity. There are few cases that banks have a policy on systematic management, system recovery and protection activities against system failure. and most developers and system administrators response based on their experience and the instinct. This article focuses on the mitigation model development for minimizing the incidents of disk unit in IT operational risks. The model will be represented by a network model which is composed of the three items as following: (1) the risk factors(causes, attributes and indicators) of IT operational risk. (2) a periodic time interval through an analysis of historical data. (3) an index or an operational regulations related to the examination of causes of an operational risk. This article will be helpful when enterprise needs to hierarchically analyze risk factors from various fields of IT(information security, information telecommunication, web application servers and so on) and develop a mitigation model. and it will also contribute to the reduction of operational risks on information systems.

• Korean Journal of Clinical Laboratory Science
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• v.41 no.2
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• pp.62-66
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• 2009

HbA1c is the major fraction of glycated hemoglobin, and used primarily to identify the average plasma glucose concentration over prolonged periods of time, mostly 2-3 months. It is used as markers for the diagnosis and monitoring of diabetic patients and increasingly used a marker in health screening check up for general populations. In this study, HbA1c was measured with Cobas integra 800 (Roche Diagnostics, Mannheim, Germany), using immunoturbidimetry principles. We established the reference interval for HbA1c with Cobas integra 800 and evaluated its significance. The study subjects were 36,140 (male 57.5%, and female 42.2%) who visited the Health Promotion Center of a tertiary care center in Seoul for health checkup from January to September, 2008. HbA1c levels were measured with immunoturbidimetric method. Statistical evaluation was done with SPSS. Comparison between male and female was checked with Mann-Whitney test, and among age groups with Kruskal-Wallis test. Reference interval for HbA1c was from 4.8% to 6.1%. There was no significant difference between male and female with Mann-Whitney test (P=0.539). There was significant difference among age groups with Kruskal-Wallis test (P<0.05). Reference interval for HbA1c with Cobas integra 800 was 4.8~6.1%, which was different from conventional one, 4.4-6.4%. Establishment of reference interval for each principle is needed.

• Journal of Korean Institute of Industrial Engineers
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• v.14 no.1
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• pp.1-15
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• 1988

DS1 transmission systems use framing bit errors, bipolar violations and code-detected errors to estimate the bit error rate when determining errored and severely errored seconds. Using the coefficient of variation under the memoryless binary symmetric channel assumption, a basic framework to evaluate these estimation schemes is proposed to provide a practical guideline in determining errored and severely errored seconds which are fundamental in monitoring the real-ime error performance of DS1 transmission systems carrying live traffic. To evaluate the performance of the cyclic redundancy check code (CRC), a computer simulation model is used. Several drawbacks of the superframe format in association with real time error performance monitoring are discussed. A few recommendations are suggested in measuring errored and severely errored seconds, and determining service limit alarms through the use of the superframe format. Furthermore, we propose a new robust scheme for determining service limit alarms which take into consideration the limitations of some estimation schemes for the time interval of one second.

• The Korean Journal of Emergency Medical Services
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• v.9 no.1
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• pp.101-109
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• 2005

The purpose of this study which was done by 250 Prehospital Care Reports(PCRs) survey of some squads in Seoul Metropolitan Fire & Disaster Management Department was to improve prehospital emergency care by means of quality management. The data were collected in 3 squads from Jun. 21 to Jul. 18, 2004 and analyzed by using SPSS Win 12.0 Version. The conclusions from this study were summarized as follows. The mean time of Event to treatment interval was $4.6{\pm}4.3$ minutes and 49.2% arrived at patient within 4 minutes. Platinum minute was observed 61.1% of verbal response, 73.3% of painful response, 77.8% of unresponsive. The great majority of patients couldn't receive advanced life support on account of limited scope of practice and strict direct medical control in the Emergency Medical Services Act. Data from quality improvement activity will be useful to expand indirect medical control which is able to activate prehospital care. To utilize PCR for quality improvement. It has to have data elements, run data, patient data, check boxes, narrative including US DOT's minimum data set.

• The Korean Journal of Nuclear Medicine Technology
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• v.17 no.2
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• pp.101-106
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• 2013

Purpose: As UBC IRMA is being tested, patients out of the reference value are reacting within the value again a few days later the urine collection tested, which causes the reliability of the test to decrease as a result. In this study, we can assume that the physiological changes in the factors would affect the results. The purpose of the study is to find out whether hematuria and proteinuria in the sample as well as the interval time (3 hours or more recommended) have affected the results. As a result, we could discover the changes in factors and increase the reliability of the test. Materials and Methods: 468 people (female: 249, male: 219) who came for the check-up were presented herein for medical examination from 2013.3.15 to 2013.1.2. Some people out of 468 who have reacted onto the reference value were divided into group low titer zone, ow-middle titer zone, and middle-high titer zone and tested for hematuria and proteinuria. During that period, 48 outpatients were asked to fill in a questionnaire regarding the urination interval time. The reagents used were (IDL Biotech AB, Sweden) and UBC IRMA. Results: Of the patients that are formed in the reference value of ($0.1-34.0{\mu}g/L$) turn out to be 52.7 years average age in their low concentration, ($mean{\pm}SD$) of the value of $0.10{\pm}0.02{\mu}g/L$. Among 80 people (50.8%, female: 49.2%), 16 patients (20%) have shown reaction to microscopic hematuria and 10 patients (12.5%) responded to proteinuria. In the average low concentration under 52.5 years of average age, 43 people (53%) have shown reaction to microscopic hematuria and 21 people (26.3%) are proteinuric patients out of 80 patients (male: 50.8%, female: 51.3%). In the middle high concentration of $11.8{\pm}4.82{\mu}g/L$ under the average age 51.7 years, 35 patients (53%) have responded to the microscopic hematuria and proteinuric patients are 26 people (39.3%) out of 66 people (men: 44%, women: 56%). In addition, in the concentration of $51.7{\pm}43.5{\mu}g/L$, some patients who get out of the reference value are observed as the average age of 52.0. 11 patients (78.6%) out of 14 (male: 35.7%, female: 64.3%) react to the microscopic hematuria. There show 6 people (42.8%) who turn out to be as proteinuric patients. As for the interval time, $1.67{\pm}3.71{\mu}g/L$ was the average value among 48 patients (female: 45.8%, male: 54.2%). Conclusion: We cannot see if proteinuria and hematuria directly affect abnormal results of inspection of 8,18 cytokeratin; however, we can find out that they statistically have an influence on highly generating UBC among several mechanisms. Also, although urination interval time was various every 15 minutes, we it does not affect these results.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.11
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• pp.1017-1021
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• 2013

The traffic signal has been widely used in the transport system with a fixed time interval currently. This kind of setting time was determined based on experience for vehicles to generate a waiting time while allowing pedestrians crossing the street. However, this strict setting causes inefficient problems in terms of economic and safety crossing. In this research, we propose a monitoring algorithm to detect, track and check pedestrian crossing the crosswalk by the patterns of behavior. This monitoring system ensures the safety for pedestrian and keeps the traffic flow in efficient. In this algorithm, pedestrians are detected by using HOG feature which is robust to illumination changes in outdoor environment. According to a complex computation, the parallel process with the GPU as well as CPU is adopted for real-time processing. Therefore, pedestrians are tracked by the relationship of hue channel in image sequence according to the predefined pedestrian zone. Finally, the system checks the pedestrians' crossing on the crosswalk by its HOG based behavior patterns. In experiments, the parallel processing by both GPU and CPU was performed so that the result reaches 16 FPS (Frame Per Second). The accuracy of detection and tracking was 93.7% and 91.2%, respectively.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.5
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• pp.20-28
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• 2014

This paper proposes a faulty node detection scheme that performs collective monitoring of a distributed networked control systems using interval weighting factor. The algorithm is designed to observe every node's behavior collectively based on the pseudo-random Bose-Chaudhuri-Hocquenghem (BCH) code. Each node sends a single BCH bit simultaneously as a replacement for the cyclic redundancy check (CRC) code. The fault judgement is performed by performing sequential check of observed detected error to guarantee detection accuracy. This scheme can be used for detecting and preventing serious damage caused by node failure. Simulation results show that the fault judgement based on decision pattern gives comprehensive summary of suspected faulty node.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.2 s.173
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• pp.535-542
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• 2000

This paper presents a method for the dynamic analysis of constrained multibody systems undergoing abrupt collision. The proposed method uses a longer time interval to check collision than that of c onventional method. This reduces the computational effort significantly. To calculate collision points on two colliding rigid bodies, one may introduce constraints of contact. However, this causes reduction of degree of freedom and difficulty of numerical analysis. The proposed method can calculate collision points without above mentioned problems. Three numerical examples are given to demonstrate the computational efficiency and the usefulness of the proposed method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.11
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• pp.5437-5454
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• 2016

A Wireless Sensor Network (WSN) is composed of several sensor nodes which are severely restricted to energy and memory. Energy is the lifeblood of sensors and thus energy conservation is a critical necessity of WSN. This paper proposes a clustering algorithm namely Energy Efficient Trustworthy Clustering algorithm (EETCA), which focuses on three phases such as chief node election, chief node recycling process and bi-level trust computation. The chief node election is achieved by Dempster-Shafer theory based on trust. In the second phase, the selected chief node is recycled with respect to the current available energy. The final phase is concerned with the computation of bi-level trust, which is triggered for every time interval. This is to check the trustworthiness of the participating nodes. The nodes below the fixed trust threshold are blocked, so as to ensure trustworthiness. The system consumes lesser energy, as all the nodes behave normally and unwanted energy consumption is completely weeded out. The experimental results of EETCA are satisfactory in terms of reduced energy consumption and prolonged lifetime of the network.