• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.48 no.7
• /
• pp.523-528
• /
• 2020

A lateral type MEMS inertial switch was designed on the same principle as spring-mass system. The MEMS switch is used for arming mechanism of the arm-fire device by sensing the applied acceleration. We analyzed the switching capability of the MEMS switch under various acceleration conditions via performance model. Simulation results showed that the MEMS switch works very well at 10 g when the applied acceleration slope does not exceed 10 g/msec. On the other hand, the threshold operating acceleration level simulation exceeded the requirement (10±2 g) due to the width and length of the spring by considering 10% tolerance of the design values. Design modification of doubling the width of the spring, which is difficult to reduce less than 10% tolerance in fabrication process, was proposed after confirming the simulation results comply the requirement.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2006.05a
• /
• pp.61-65
• /
• 2006

A thery was developed to design a high pressure vessel with combined structure of the metal and the composite to withstand the pressure of several tens of thousands psias to reduce the weight of the impulse motor which produces high level of thrust within several tens of seconds. The elastic-plastic stress analyses were carried out to prove the validity of the design theory A combustion chamber of the impulse motor was designed by the design theory, fabricated, and tested by the hydraulic pressure and the static firings. The bursting pressures from the tests were compared to those predicted by tile design theory and the stress analyses and found to be almost the same. It will be possible to design the high pressure vessel with combined structure of the metal and the composite very easily by the proposed design theory.

• The Journal of the Korea Contents Association
• /
• v.15 no.4
• /
• pp.197-207
• /
• 2015

In this research, Check the problems through analysis of traffic accidents while the elderly walking. Propose a way to reduce elderly traffic accidents. Therefore, analyzing the characteristics(by time and place etc) in order to reduce the traffic accident in the elderly pedestrian. Proposed the following Policy alternatives. First, Build a pedestrian safety island on the center of the road. Secondly, Should install the pedestrian crossing signal facilities which show the spare time and the guard rail to prevent crosswalk. Third, Should expend the installation area of pedestrian-operating traffic signal. Fourth, the night lighting facilities shall be installed nearby Crosswalk. Finally, Should appoint the elderly care area. Measures presented in this study, I hope they can be the basic data for the elderly in traffic safety policies for the elderly in accordance with the advent of aging society.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.4 no.4
• /
• pp.61-69
• /
• 2001

Recently, according to the rapid development of computer and electronic technology, most crude oil carriers adopt automated cargo handling system. But an excessive automation makes system so complicate that it could increase the Possibility of accidents due to human error. Although a cargo handling process is done by an expert, the potential of accidents by human factor lies through the whole cargo handling procedure and the current automated system lacks of the functionality to prevent a mis-operation and diagnose the abnormal status of the system. Because the oil concerned accident could be almost a disaster, the primary goal of system development should not be a fully automated system but be a perfectly safe system. This paper deals with the analysis and design of an expert system which can provide mariner with the operational guidance and the facility of crisis management by monitoring system's abnormal condition and human's mis-operation.

• Journal of Navigation and Port Research
• /
• v.40 no.4
• /
• pp.189-196
• /
• 2016

We propose a virtual sailor training platform which supports emergency drills for ship's fire in virtual environment. Proposed platform not only enhances training efficiency by providing immersiveness, but also enables a consolidated virtual training due to the network-based multiplayer capabilities. Based on the offline fire simulation results using FDS and CFAST the platform visualizes a realistic fire spread in real-time. The training platform on the basis of the fire training material of the maritime safety education institute induces equipment proficiency and environment adaptation throughout immersive virtual environment in addition to procedure proficiency as well. In the implementation we showed that the equipment and environment controls and telepresence improve the training proficiency and enable collaborative virtual training that participates multiple trainees and induces cooperation for a common goal. Implementation of the platform demonstrated the skill mastery capability of the drill such as efficient fire apparatus controls and passenger controls.

• Korean Chemical Engineering Research
• /
• v.54 no.3
• /
• pp.360-366
• /
• 2016

The Propulsion Test Facilities for the development of Korea Space Launch Vehicle-II are being built, some test facilities are completed and various combustion tests are running. The Propulsion Test Facilities consists test-stand, which carries out tests for engine development model, and various sub-systems and vessels containing LOX and Jet A-1 as propellant. There are always risks of fire and explosion at the test-stand since engine development model is conducted at test-stand with real combustion test with very high pressure, mixed propellant and high energy. In this paper, in order to establish the consequence analysis and risk reduction measures in the Propulsion Test Facilities, followings are considered. 1) a propellant leak accident scenario is assumed in test-stand. 2) TNT equivalent model equation based on blast wave of the explosion was used to analyze blast overpressure and impacts. Also, technical, systematic and managemental measure is described to ensure risk reduction for propulsion test facility.

• Korean Chemical Engineering Research
• /
• v.58 no.4
• /
• pp.581-587
• /
• 2020

In this study, a new reaction system is proposed to solve the problems of the existing 2,3-Butanediol (2,3-BDO) dehydration reaction system. It was confirmed that the reaction system did not wok as it should operate properly when using a furnace, which is commonly used in commercial processes, to raise the reactant, 2,3-BDO, to the reaction temperature, 360 ℃, at near atmoshperic pressure. It is because of the substance considered to be oligomers of 2,3-BDO. It can lead to safety problems, such as blockages inside the furnace's tube and explosions, as well as tricky maintenance issues in the reaction system. To solve it, the temperature of reactant can be brought down by using a heat exchanger with High Pressure (HP) steam instead of the furnace, which has a hot spot problem through the vacuum operation and reduce the reaction temperature. It can be seen that the reactor performance is almost similar under the vacuum operation and the lower reaction temperature, 330 ℃, by using a reaction kinetics. This result explains why the new reaction system is proposed.

• Journal of the Korean Society for Railway
• /
• v.10 no.6
• /
• pp.779-785
• /
• 2007

This study identifies visible/invisible factors and analyzes facilities, structure, and visible perceptive contents in the aspects of operation and efficiency with a focus on the interfaces between interior design of the subway and users. More specifically, it diagnoses the requirements and empirically presents improvements. As the interior design in the subway trains is fur the public reflecting the value, consciousness, and behaviors of users, it should be approached through the application of the concept of universal design that considers the potential needs and psychological satisfaction of users. In arranging the indoor of the vehicles, the conditions for the facilities should be specified through the interdisciplinary approach from professional fields including ergonomics and psychology, the path of flow should be induced through the use of space and the analysis of passengers' behaviors, an integrated planning should be re-established, and continuous evaluations of basic guidelines, manuals, and requirements should be made.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.20 no.8
• /
• pp.1615-1622
• /
• 2016

This research aims to develop a voyage performance monitoring system based on international standards. The developed system is equipped with an electronic navigational chart(ENC) that provides onshore and offshore information, as well as supports standardized interfaces with navigational equipment, such as a gyro compass, a differential global positioning system(DGPS), and an automatic identification system(AIS), to monitor the navigation route in real time. In addition, the proposed system adopts a car navigation system to provide a graphical user interface, an intuitive menu-driven configuration, and an easy guide for safer sea navigation. The system, interfaced with the gyro compass and DGPS, was verified without any data loss, and passed a test conducted under extreme conditions by the Korea Laboratory Accreditation Scheme(KOLAS). Finally, the system contributes to preventing collision of vessels and minimizing casualties by maximizing the convenience of mariners which a conventional system does not provide.

• Journal of KIISE
• /
• v.43 no.10
• /
• pp.1094-1103
• /
• 2016

Physical Web and Eddystone can be serviced by a single integrated application on the device by using their servers' URL. However, they have a limitation that their servers must be customized for service characteristics on a case by case basis. In other words, regardless of the service selected for BLE, it should have a modified linkage application for each device. Hence, we think that a new integrated service platform, which is able to link and support its Beacon from the central server and is also able to support its application, is needed for achieving better service quality. This platform consists of push (Broadcasting for Beacon service) parts and pull (Connection) parts to establish communication. Especially, Pull should be operated and controlled under the authorization (secure) management for safe and trustable communication. It means that BLE must have its new authorization communications protocol to protect its data as much as possible. In this paper, we propose a BLE integrated authorization protocol for a BLE device control server based on Physical Web and Eddystone.