• Journal of Industrial Technology
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• v.16
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• pp.207-216
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• 1996

This paper develops an algorithm for throughput of a 3-stage flow line with job inspection stations, limited buffer capacity, and exponential processing times. Each stage consists of a single workstation, and an infinite number of jobs always waits in front of the first workstation. Blocking may occur when a processed job is waiting at one workstation for another workstation to become available. Numerical example results provide insights into the problems related to quality inspection and measure of performance of flow lines.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.3
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• pp.147-155
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• 2016

Industry 4.0's goal is the 'Smart Factory' that integrates and controls production process, procurement, distribution and service based on the fundamental technology such as internet of the things, cyber physical system, sensor, etc. Basic requirement for successful promotion of this Industry 4.0 is the large supply of semiconductor. However, company I who produces dicing blades has difficulty to meet the increasing demand and has hard time to increase revenue because its raw material includes high price diamond, and requires very complex and sensitive process for production. Therefore, this study is focused on understanding the problems and presenting optimal plan to increase productivity of dicing blade manufacturing processes. We carried out a study as follows to accomplish the above purposes. First, previous researches were investigated. Second, the bottlenecks in manufacturing processes were identified using simulation tool (Arena 14.3). Third, we calculate investment amount according to added equipments purchase and perform economic analysis according to cost and sales increase. Finally, we derive optimum plan for productivity improvement and analyze its expected effect. To summarize these results as follows : First, daily average blade production volume can be increased two times from 60 ea. to 120 ea. by performing mixing job in the day before. Second, work flow can be smoother due to reduced waiting time if more machines are added to improve setting process. It was found that average waiting time of 23 minutes can be reduced to around 9 minutes from current process. Third, it was found through simulation that the whole processing line can compose smoother production line by performing mixing process in advance, and add setting and sintering machines. In the course of this study, it was found that adding more machines to reduce waiting time is not the best alternative.

• Journal of the Korean Institute of Rural Architecture
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• v.12 no.4
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• pp.29-36
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• 2010

The purpose of this study is to have detailed data of the distribution, locations, and the amount of people in the waiting line of the nursing home. Also, we studied the accessibility to the facilities by using Web GIS to analyze the transit time it takes from the nursing home to health center and hospitals. We can provide the basic data that could contribute when future plans for the nursing homes' locations, health and medical policy are made. The results are as follows. 1. The nursing homes are stiffly concentrated in regions of Seoul and Gyeongi-do where large number of the elderly covered by long-term care insurance and the waiting line was very long for the elderlies to enter the nursing homes. In these cities of Ulsan and Jeju where number of the elderly covered by long-term care insurance is relatively small, there were less facilities. 2. The nursing homes located in urban areas had higher occupancy rate and higher number of people in the waiting line. 3. The average time taken by driving from the nursing homes and health center was 10 minutes and there was not a noticeable difference between the cities. Driving from the nursing homes to hospitals in rural areas took 22 minutes which is 2.5 times of the time taken for urban areas. Daegu-si and Incheon-si had relatively short distance from the nursing homes and the hospitals while Jeju-do had the furthest. For rural areas, it is needed for health center to be equipped with a wider medical coverage, have closely connected with hospitals to minimize the differences they have from ones in rural areas. It is also needed to have ambulances equipped for tele-medical examination and treatment system.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.23 no.3
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• pp.261-265
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• 2013

The purpose of this study was to evaluate noise level exposures at different locations such as the left and right ears of the shooter, control room, waiting soldier location and drill ground. For this study, we visited two military rifle ranges and took measurements with a sound level meter (3M Quest SoundPro TM) at five different locations with values of Peak (dB(A)) and Max (dB(A)). The highest peak value of impulse noise level averaged 150.4 dB(A), ranging from 149.6 to 150.5 dB(A) at both the left and right ear sides. This result was significantly different between both left and right ear side locations and at other locations such as the control room, waiting soldier location, and drill ground (P < 0.001). Frequency of impulse noise exposure level showed that the left ear of shooter had the highest frequency (20 times) at over 150 dB(A). This study confirmed that there is a need for proper controls to reduce the amount of impulse noise exposure at military rifle ranges.

• Korean Journal of Child Studies
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• v.16 no.1
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• pp.147-165
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• 1995

The purpose of this study was to examine the entry behaviors of kindergarten children into peer dyads and the responses of the peer dyads in relation to the sex and sociometric status of the entering child. The subjects were 46 triads(138 children). Each triad consisted of two children of average peer status and one child of high/low peer status, identified by the Peer Rating Scale. The two children of the average peer status were placed in a small laboratory and were given a game to play. After the game had started, the child of high/low peer status entered into the laboratory. The behaviors of the entering child and the responses of the peer dyads were videotaped for 6 minutes. The data were analyzed by sex(2)${\times}$sociometric status (2) ANOVAs and ${\chi}^2$-tests. The results were as follows: (1)Popular children showed more group-oriented statements and fewer waiting behaviors than non-popular children. (2)Popular children elicited more positive responses and were less ignored than non-popular children. (3)The peer group responded positively to the entering child's helping, agreeing, and giving group-oriented statements, and neglected the entering child's waiting behaviors.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.5
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• pp.675-684
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• 1993

In this paper, we analyze a traffic control schemes at the interworking unit(IWU) of the IEEE 802.6 DQDB MAN and the B-ISDN, and estimate its performance via computer simulation. We also study traffic management, relaying sublayers for the cases of four service classes defined in the B-ISDN. As for performance criteria, we consider slot waiting time, slot loss rate, and the fairness between DQDB nodes in access networks. We propose a simple control algorithm that decreases the waitint delay at the OWU. With the buffer size of 40 [slots] at the IWU, we have found that the slot loss rate was nearly zero at traffic load below 0.9, and the slot waiting time became less than 15 slot times.

• Child Health Nursing Research
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• v.11 no.4
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• pp.444-455
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• 2005

Purpose: This study examined the efficacy of parent training interventions to facilitate social reciprocity and language development in children with autism. Methods: The social interaction behaviors of mothers and children over time were compared using single subject design experimentation methodology. five children who were diagnosed with autism and their mothers participated in the study. The participants were recruited from U city, Korea. The mothers were trained using training videotapes and demonstrations on how to facilitate social interaction with their children as well as promoting language development. following the training, data were collected three times per week by video taping mother-child interaction in their homes. Results: Four of the five mothers demonstrated increases in the use of imitation with animation and expectant waiting after the intervention compared to the baseline sessions; the children demonstrated noticeable increases in the use of initiation of interaction, vocalizations, and verbal production after their mothers received the training intervention. Conclusion : Results of this study demonstrate the efficacy of mother training to improve social interactions of children with autism. Additional important information can be gained by replicating this study with more participants and comparing intervention and control groups. Clearly, this intervention shows promise and has implications far clinical practice.

• The Journal of Korean Academic Society of Nursing Education
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• v.29 no.4
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• pp.339-351
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• 2023

Purpose: The purpose of this study is to identify the educational needs of virtual reality simulations that can be applied to novice nurses during the waiting period before starting work in a hospital. Methods: A convergent mixed methods was used. The survey data were collected from 230 novice nurses, and a focus group interview was conducted with 6 new nurses. The data were collected from November 2022 to January 2023. Descriptive statistics, a frequency analysis, independent t-test, and an Importance-Performance Analysis were performed using SPSS 24.0. Results: Appropriate topics for virtual reality simulation education were indicated to be medications and intravenous injections, which are high priority topics in quantitative and qualitative research. The novice nurses wanted group activity training three to four times a week for two weeks before beginning work in a hospital. They also wanted an immersive virtual reality system based on a real hospital environment. Conclusion: Based on the above results, this study provides basic data for the development of a virtual reality simulation education that can improve the adaptation of novice nurses to clinical practice. A strategy was suggested to utilize the waiting time before beginning work in a hospital as educational time.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.47 no.1
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• pp.20-27
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• 2024

Determining the number of operators who set up the machines in a human-machine system is crucial for maximizing the benefits of automated production machines. A man-machine chart is an effective tool for identifying bottlenecks, improving process efficiency, and determining the optimal number of machines per operator. However, traditional man-machine charts are lacking in accounting for idle times, such as interruptions caused by other material handling equipment. We present an adjusted man-machine chart that determines the number of machines per operator, incorporating idleness as a penalty term. The adjusted man-machine chart efficiently deploys and schedules operators for the hole machining process to enhance productivity, where operators have various idle times, such as break times and waiting times by forklifts or trailers. Further, we conduct a simulation validation of traditional and proposed charts under various operational environments of operators' fixed and flexible break times. The simulation results indicate that the adjusted man-machine chart is better suited for real-world work environments and significantly improves productivity.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.3
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• pp.663-670
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• 2015

In most public transportation related master plans, decisions for investment priorities are initially made by facilities with lower installation rates or lower satisfaction (performance) levels. In general, the decisions are made without conducting importance factor analysis. In this study, a combined method of importance-performance analysis (IPA) model for bus users related in travel time is proposed by using Structural Equation Model (SEM). The results of the IPA for Metropolitan users show that the categories need improvement are number of bus stops, number of intersections, headways, waiting times for boarding and traffic signal operations in order. On the other hand, Non-Metropolitan uses show that the categories need improvement are traffic signal operations, waiting times for boarding, headways, bus exclusive lanes and number of intersections that is in reverse order to Metropolitan users.