• Journal of the Korean Society of Safety
• /
• v.8 no.4
• /
• pp.133-138
• /
• 1993

The stable and safe operation of a boiler system is essential for ensuring stability of the chemical processes. A dynamic simulation of a boiler drum was performed to identify the dynamics of the boiler drum. The obtained results represented that the variation of process variables disturb boiler system. So, disturbance rejection with tracking and constraints handing was necessary for stable operation of boiler drum. Among many controller, GPC has been known to show good performance in set point tracking than disturbance. In order to improve disturbance rejection performance measurable disturbance term was Introduced in basic GPC model. The controller which had tracking and disturbance rejection was designed for Improving the stable operation of a boiler system.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.19 no.11
• /
• pp.803-809
• /
• 2007

To those who spend most time within a room, comfortable indoor environment is a very critical element to job performance and health. The comfort technology, which is for enhancing comfort in human living, relates with various factors to ensure human activities efficient, comfortable, safe and satisfactory. Experiments were performed in environmental chamber. Experimental conditions were combinations from three temperatures of 18, 22 and 26C, and two relative humidity levels of 45 and 60%. Air-flow was controlled to 0.1m/s through the experiment. Four male and four female university students participated in the experiments. They had normal blood pressure and their body temperature was under $37^{\circ}C$. From the experiments for evaluating thermal sensation to the air-heating conditions, relationships among TSV, CSV, $SET^*$, PMV were analyzed. Results can be summarized as followings; Thermal neutrality $SET^*$ of man and female was $24.8^{\circ}C$. In air-heating condition, $SET^*$ values for thermal comfort zone were $23.0{\sim}26.5^{\circ}C$. These values were higher than the values from ASHRAE.

• Journal of Nutrition and Health
• /
• v.42 no.2
• /
• pp.128-134
• /
• 2009

For children, voluntary addition of micronutrients to foods must be done without health risk to any of them. This study examined safe maximum levels of vitamin A and C, and calcium for children based on nutrient intake data from the 2001-2002 and 2005 National Health and Nutrition Examination Survey (NHANES) in Korea, while using the safe strategy for addition of micronutrients to foods suggested by EU. For the respective 2001-2002 and 2005 NHANES data proportions of potentially fortifiable energy intake ranged 0.36-0.40 and 0.31-0.34 and the $95^{th}$ percentile intake of energy were 2,325-3,296 kcal and 2,286-3,814 kcal depending upon age groups. Ninety-fifth percentile intake levels of vitamin A were over or close to UL, even without considering supplement intake for some age groups, which suggest that vitamin A fortification to foods required further consideration. For calcium, 12-14 year old children were the most sensitive group for excessive intake and nutrient fortification to foods. In these children, maximum levels for fortification were 242-290 mg and 484-580 mg with 0.135 and 0.068 proportions of fortified food (PFF) assumed, respectively, without considering calcium intake from supplements. With consideration of calcium intake from both diet and supplement, the maximum levels for fortification were 20-36% of those without supplement intake. The maximum fortification levels of vitamin C were the lowest in 3-5 year old children, showing 77-187 mg and 68-164 mg with and without supplement intake, respectively. These results suggest that the model used for risk assessment in this study can be used to help risk managers to set maximum levels for safe addition of micronutrients to foods.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.10 no.6
• /
• pp.253-260
• /
• 2015

In this study, using the FDS as the fire simulation and evacuation simulations of the Pathfinder, set the main control room of the building to the fire point fire safety assessment studies were carried out. At first the quantitative result such as distribution of visibility as time passing, distribution of temperature, distribution of CO density produced results using fire-simulation and evacuation-simulation was carried out based on the result that produced the final safety evaluation result as being calculated of evacuation time. As the risk increased with the distribution of visibility at the result of fire-simulation, evacuation-simulation was carried out using the result. Finally the result was made 127.9 sec that everyone could evacuate. The numerical results are analyzed in case of the places in the building required safe egress time for safety a as the analysis to be no more than available safe egress time was analyzed to be secured. The results of this safety evaluation represent that more smooth evacuation safety performance can be secured by linking the event of fire firefighting equipment as a result of simulating the worst conditions.

• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10b
• /
• pp.1480-1483
• /
• 1996

A set of approaches suggested to control the eccentricity is discussed in this paper. Among these, filter-integrator method is used to design the controller, which also includes the input signal synchronization, stabilizing filter and eccentricity source discrimination. Using the S/W that is coded for real time application of that controller, we simulated the operations of that one. The simulation results show the characteristics of eccentricity compensation and eccentricity discrimination. However, from these results, we can see that only proper stabilization strategy certificates the safe eccentricity control.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.10 no.1
• /
• pp.8-15
• /
• 2011

ATV(All Terrain Vehicle) has been developed to be used for agricultural fields on unpaved roads but now it is mostly used to transport a short distance and play leisure sports at mountains. Recently, main concerns on the automobile industry is developing not only a car safe, high fuel efficient and friendly related with environment but also two-wheeled vehicles. In order to maintain high fuel efficiency and safety of two-wheeled vehicle, it is essential that ATV should be set up differential gear. But we worried for ATV which had been set up differential gear not to run on unpaved roads. Therefore, it is necessary to develop LSD(Limited Slip Differential) that maintains existing advantages of ATV and ensures ATV to travel safely on roads. Now LSD equipped cars have a complicated structure, so setting up on ATV is unsuitable. Therefore, in this study, we have developed simple, small and well operating LSD.

• Journal of Advanced Marine Engineering and Technology
• /
• v.34 no.3
• /
• pp.407-412
• /
• 2010

According to the remarkable advances in sonar technology, positioning capabilities and computer processing power we can accurately image and explore the seafloor in hydrography. Especially, Multibeam Echo Sounder can provide nearly perfect coverage of the seafloor with high resolution. Since the mid-1990's, Multibeam Echo Sounders have been used for hydrographic surveying in Korea. In this study, new marine data set as an effective decision-making tool in various fields was proposed by visualizing and combining with Multibeam sonar data and marine spatial data sets such as satellite image and digital nautical chart. The proposed method was tested around the port of PyeongTaek-DangJin in the west coast of Korea. The Visualization and fusion methods are described with various marine data sets with processing. We demonstrated that new data set in marine GIS is useful in safe navigation and port management as an efficient decision-making tool.

• Restorative Dentistry and Endodontics
• /
• v.46 no.4
• /
• pp.50.1-50.8
• /
• 2021

Although several techniques have been proposed to remove fiber-reinforced composite (FRC) post, no safe and efficient technique has been established. Recently, a guided endodontics technique has been introduced in cases of pulp canal obliteration. This study describes 2 cases of FRC post removal from maxillary anterior teeth using this guided endodontics technique with a dental operating microscope. Optically scanned data set from plaster cast model was superimposed with the data set of cone-beam computed tomography. By implant planning software, the path of a guide drill was selected. Based on them, a customized stent was fabricated and utilized to remove the FRC post. Employing guided endodontics, the FRC post was removed quickly and safely with minimizing the loss of the remaining tooth structure. The guided endodontics was a useful option for FRC post removal.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.8B
• /
• pp.805-811
• /
• 2009

Firstly, this dissertation suggests the tag ID transfer method using two-dimensional arrangement. Secondly, provide better and stable security system compare to existing one by transferring tag; ID using established two-dimensional arrangement. Thirdly, provide operating module, which possible to descramble two-dimensional arrangement, with a character set when descrambling in a tag and a server. Lastly, suggest safe key transfer using a character set and two-dimensional arrangement. In order to embody suggested system and assess, transferred two-dimensional arrangement several times to carry out the experiment. Confirmed that it is impossible for suggested system to decode key patterns compare to existing RFID systems.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.2325-2330
• /
• 2005

A potential field method for solving the problem of path planning based on global and local information for a mobile robot moving among a set of stationary obstacles is described. The concept of various method used path planning is used design a planning strategy. A real human living area is constructed by many moving and imminence obstacles. Home service mobile robot must avoid many obstacles instantly. A path that safe and attraction towards the goal is chosen. The potential function depends on distance from the goal and heuristic function relies on surrounding environments. Three additional combined methods are proposed to apply to human living area, calibration robots position by measured surrounding environment and adapted home service robots. In this work, we proposed the application of various path planning theory to real area, human living. First, we consider potential field method. Potential field method is attractive method, but that method has great problem called local minimum. So we proposed intermediate point in real area. Intermediate point was set in doorframe and between walls there is connect other room or other area. Intermediate point is very efficiency in computing path. That point is able to smaller area, area divided by intermediate point line. The important idea is intermediate point is permanent point until destruction house or apartment house. Second step is move robot with sensing on front of mobile robot. With sensing, mobile robot recognize obstacle and judge moving obstacle. If mobile robot is reach the intermediate point, robot sensing the surround of point. Mobile robot has data about intermediate point, so mobile robot is able to calibration robots position and direction. Third, we gave uncertainty to robot and obstacles. Because, mobile robot was motion and sensing ability is not enough to control. Robot and obstacle have uncertainty. So, mobile robot planed safe path planning to collision free. Finally, escape local minimum, that has possibility occur robot do not work. Local minimum problem solved by virtual obstacle method. Next is some supposition in real living area.