• Journal of Aerospace System Engineering
• /
• v.13 no.4
• /
• pp.1-9
• /
• 2019

Integration of satellites with diverse missions, such as broadcast-communication, earth, meteorologicaland marine observations, and navigation, is vulnerable. The problems of the currently constructed ground station network were analyzed by constructing the test environment. Based on this, we designed a network that was capable of operating multiple satellites by one ground station. In addition, we proposed an interface and network configuration method with domestic and foreign ground stations. The network linking the domestic and foreign ground stations was composed of KREONET (Korea Research Environment Open Network) and GLORIAD (Global Ring Network for Advanced Application Development) of the KISTI(Korea Institute of Science and Technology Information). The internal network consists of VPN (Virtual Private Network), DMZ(De-Militarized Zone), and 1-way USB and so forth. By constructing the network by using the proposed method, harmful data, such as virus inflow and infection, can be blocked.

• The Korean Journal of Archival Studies
• /
• no.40
• /
• pp.3-27
• /
• 2014

The purpose of the enactment of the 'Law on the National Archives of Korea' should be to secure the accountability and to shape up the improved governance system in the field of records and archival management, which will contribute to the strengthening of democracy in records management and eventually to the widening of the democratic progress in Korea. On the basis of the above recognition and by way of notion called 'horizontal accountability', this paper suggests the way to secure the National Archives of Korea's independency. And the way to reorganize the National Records Management Committee based on the pluralism and the 'multi-layered' governance system is also investigated. One of the main directions in the suggested law should be for the autonomy and transparency in the operation of the National Archives of Korea. This paper tries drawbacks and limitations of the 'Bill on the National Archives of Korea' introduced to the National Assembly last year, and suggests the alternatives as wel lto get further forward with related discussion.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.39 no.3
• /
• pp.30-38
• /
• 2016

Shuttle-Based Storage/Retrieval System (SBS/RS) is relatively new to industry. The system is in the category of Automated Storage/Retrieval System (AS/RS), but it is different in that the SBS/RS uses shuttles as Storage/Retrieval (SR) machine instead using a stacker crane. The shuttles are assigned to each tier on multi-tier system and operated for pick-up or drop-off order. Since the system can handle multiple orders simultaneously, it can provide much higher throughput than that of general AS/RS with single stocker crane. Thus, this new system is well fit to recent tendency of increasing small quantity batch production and orders. One of the drawback of this system is that it needs a lot of investment to set up. The efficient operation of the system would be one of the critical matters to increase economic efficiency of capital investment. In this study, we focused on the dwell point policy for shuttles to find efficient way of operating the system. There are four basic policies for the dwell point and we had simulation-based experiment for two different scenarios based on the speed of the shuttle and inter-arrival time of the loads coming to the system combined with four different policies. As it was mentioned above, this SBS/RS relatively new to the field and there is no such experiment shown on previous research and the study of dwell point policy for this SBS/RS could provide the direct comparison of each policy with different hardware specification; the capability of the system. The policy that achieves most efficient operation among the given environment is proposed and the usability of the system is discussed.

• Journal of the Korean Society of Safety
• /
• v.33 no.5
• /
• pp.92-100
• /
• 2018

According to 'The Analysis of Industrial Accidents in 2016' by Ministry of Employment and Labor, the number of deaths caused by accidents in the construction field is 391, accounting for 47% of 826 industrial fatalities in all industries. The breakdown of the 391 fatalities of the construction industry shows that 'struck by an object' accident had 30 fatalities, the 3rd in frequency following falling (235) and crashing (32) accidents. This study aims to explore ways to reduce the 'struck by an object' accident with emphasis on safety education and certificate system for rigging and slinging works. This study reviews literature on rigging and slinging works and analyzes 'struck by an object' accidents. The rules and regulation on the rigging and slinging works are also reviewed both for Korea and other countries with best practices in construction safety such as Singapore, Japan, U.K., and U.S. The rigging and slinging certificate systems of those countries are also reviewed to find any advantage in the construction safety management. In addition, a pilot rigging and slinging certificate system was executed in one of domestic construction site followed by two surveys: one on the riggers who participated in the pilot operation and the other on general managers in domestic construction sites. Based on the analysis of the 'struck by an object' accidents and pilot operation, this study proposes a rigging and slinging certificate system to reduce accidents, enhancing safety condition of construction sites. The certificate system was proposed in a way to accommodate working practice of construction sites. Depending on rigging careers and a crane load capacity, riggers are eligible to apply either basic or master certificate which makes difference in the level of rigging works. The safety condition of rigging and slinging work could be substantially enhanced if workers, managers, supervisors, administrators, and policy makers work together consistently.

• Korea Journal of Hospital Management
• /
• v.9 no.3
• /
• pp.128-142
• /
• 2004

To evaluate the effects of critical pathway on the length of hospital stay, the cost and quality of care provided to gastrectomy patients in a tertiary care academic medical center. The basic research design is a retrospective case-control comparative study. 470 patients of gastrectomy were included in the study; 180 before pathway development (control), 163 right after pathway implementation (path group I) and 127 one year after pathway implementation (path groupII). 476 patients of modified radical mastectomy were also analyzed to examine whether the reduction of the length of hospital stay is from the hospital-wide trend or due to the critical pathway. Death after operation, ICU stay, unplanned re-operation, readmission after discharge, the length of hospital stay and cost were analyzed. 2-test, one-way ANOVA, Bonferroni and Turkey's test were used for statistical analysis. (1) There were no significant differences in patient clinical conditions and no sign of deterioration of quality from critical pathway. (2) The length of hospital stay was 13.0 days in control group, 12.2 days in path group I and 10.0 days (p<0.01) in path groupII. (3) The total costs during the hospital stay were reduced. However the cost per day was significantly increased from reduction of hospital stay (358,488won in control, 366,017won in path group I and 413,220won (p<0.01) in path groupII). Critical pathway reduced the length of hospital stay, total hospital costs and resource utilization without harming quality of patient care.

• The Korean Journal of Community Living Science
• /
• v.20 no.2
• /
• pp.263-274
• /
• 2009

The objective of this study is to verify work satisfaction of school food-service employee, of their job characteristics. Subjects were comprised 9 elementary schools, 11 middle schools, and 3 high schools in Ansan city. Data were analyzed 203 questionnaires for frequency, means, one-way ANOVA, $Scheff{\acute{e}}$ test, t-test, and Pearson correlation using SPSS PC Package. Most of the respondents were high school graduate(91.1%), under one million won salary(41.9%), and non license holder(60.6%). Working conditions were part-time job(41.9%), unlimited contractors(51.2%), and 3-5 years of working experience(21.7%). Measure of overall job satisfaction by Likert-type 5 scale, satisfaction of work operation attitude was 3.55 points and work characteristic duty of 4.32 points. The certificate qualified and elementary school's working posture were more satisfied their work attitude than other groups(p<0.05). Salary satisfaction score showed 2.64 points, but the work esteem satisfaction showed 3.34 points. The factor of working circumstance and potentiality satisfaction was only 2.61 points, but interpersonal connection and communication satisfaction was 3.50 points. Between job satisfactions factors, they were highly correlated with each other. The pride and characteristic duty of the work showed the strongest correlated(p<0.001). The satisfaction score of work operation attitude were significantly correlated with characteristic duty(p<0.001), work esteem, interpersonal relationships and communication(p<0.01). With this results, work satisfaction of food service employees showed a relatively high to perform a job task characteristics and work attitudes. However, the working environment and growth in salaries satisfaction were low. A set of duties must be paid according to the labor intensity. As removing the disturbing factors, the improvement in the quality of the feed will be able to expect substantial effects.

• Proceedings of the KSR Conference
• /
• 2003.10c
• /
• pp.236-246
• /
• 2003

This paper is implemented a control algorithm in order to be stable and minimized to entire train traffic system at delayed case. Signal ing system is described wi th algebraic equations given for train headway, Discrete-event simulation principles are reviewed and a demonstration block signaling model using the technique is implemented. Train congestion at station entrance for short headway operation is demonstrated and the propagation of delays along a platform of trains from any imposed delay to the leading train is also shown. A rail way signaling system is by nature a distributed operation with event triggered at discrete intervals. Although the train kinematic variables of position, velocity, and acceleration are continually changing, the changes are triggered when the trains pass over section boundaries and arrive at signals and route switches. This paper deals with linear-mode1ing, stability and optimal control for the traffic on such metro line of the model is reconstructed in order to adapt the circuits. This paper propose optimal control laws wi th state feedback ensuring the stability of the modeled system for circuits. Simulation results show the benefit to be expected from an efficient traffic control. The main results are summarized as follows: 1. In this paper we develop a linear model describing the traffic for both loop lines, two state space equations have been analyzed. The first one is adapted to the situation where a complete nominal time schedule is available while second one is adapted when only the nominal time interval between trains is known, in both cases we show the unstability of the traffic when the proceeding train is delayed following properties, - They are easily implemented at law cost on existing lines. - They ensure the exponetial stability of loop system. 2. These control laws have been tested on a traffic simulation software taking into the non-linearites and the physical constraints on a metro line. By means of simulation, the efficiency of the proposed optimal control laws are shown.

• Strategy21
• /
• s.44
• /
• pp.291-322
• /
• 2018

This research aims to cast light upon security characteristics of the Peace Line, which have been underestimated. To understand maritime order and maritime security policy of the Republic of Korea between 1950 and 1970, it is necessary to analyze the Peace Line as line of defence and to investigate its character This research begins with analyzation of historical facts and investigation on security characteristics of the Peace Line. It goes further to examination of legal justification of the Peace Line, which was one of international legal issues of the period, principally regarding its security characteristics. As results of the study, it could be said that the security characteristics of the Peace Line was the line of defensive waters, which set its goal mainly to prevent infiltration of communist spies. The Peace Line had practical effect as it functioned as a base line of the ROK Navy to take anti-spy operation. At the early phase of the Korea-Japan Negotiation, the Korea delegation interpreted significance of the Peace Line passively. After abrogation of Clark Line, the delegation, however, became positive to maintain the Peace Line and its security characteristics. Security characteristics of the Peace Line was recognized again, as it became the base line of special maritime zone which was made in 1972. Through analysis on international law, it is concluded that the Peace Line was fair as a part of the right of self-defense against indirect aggression. North Korea attempted indirect aggression mainly from sea way, and these might undermine peace and cause urgent and unjust damage on the ROK. Thus the ROK's action of anti-spy operation through the Peace Line can be justifiable as considering the right of self-defence. Also the Peace Line accorded with principles of necessity, immediacy and proportionality. As it was argued on the above, the Peace Line as line of defence was one of the most significant factor in the ROK's maritime security history from the Hot war against communist forces to Cold war period after Korean War and must not be underestimated.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.66 no.12
• /
• pp.1905-1912
• /
• 2017

In recent years, Ulaanbaatar, a capital of Mongolia has witnessed major problem that air quality reaches hazardous level during the winter season. Coal combustion for heating of every house in "Ger" district is main reason. One way to reduce the air pollution is mass usage of electric heater. However, there are several difficulties such as overload and degradation of transformers and other equipment used in distribution and transmission systems as well as power shortage occurrence in evening peak period due to residential consumption. This study aims to contribute for solving the air pollution and power shortage problem in Mongolia. One possible solution could be distributed generation (DG) with photovoltaic (PV) penetration. In this study, PV with energy storage (ES) hybrid system to reduce peak load is analyzed. We proposed the suitable structure of PV-ES hybrid for Mongolian household, and suggested several operation scenarios. Optimal operation algorithm is carried out based on a comparison aspect from economical, grid impact and PV penetration possibility. The economic analyse shows annual income of 520USD, and has a payback period of 8 years for selected scenario. The proposed PV-ES system structure is verified by experimentation set on the building rooftop in city center. The suggested scenario is planned to apply for system in further research.

• Journal of the Korean Institute of Gas
• /
• v.21 no.1
• /
• pp.34-42
• /
• 2017

We developed the safety training methods which improve the current methods by overcoming the single scenario-based one-way communication between trainee and training system. We improved the design and implementation of the safety training scenarios, which is one of the most important components of the plant safety training system for safe operation of the city gas governor. The diversity and training effects of the training scenarios can be improved by interactive training between the plant safety training system and operators. The interactive training methods were developed based on Finite State Machine model which is applicable to and based on plant safety training platform. We could see the possibility of applying this method of safety training scenario system to other domain of plant safety training system.