• Proceedings of the KIEE Conference
• /
• 2005.10b
• /
• pp.385-387
• /
• 2005

In this study, we tried to implement a PDA (Personal Digital Assistant)-based audiometric system to test hearing disorder. Due to the inherent handy nature of PDA system, our hearing test system can be easily performed in a local environment and consequently the measured audiometric data are stored and queryed via a built-in a PDA database system.

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 1983.10a
• /
• pp.112-117
• /
• 1983

In this paper, a functional m-redundant system, which is me-fault tolerant, is defined based on the graph-theory. This system is designed to be t fault-diagnosable by comparing its unit's outcomes without additive test functions, and so, the system down for diagnosis is not needed. the diagnostic model for this system is presented and this effectively uses system's redundancy. It is shown that this model can be converted into Preparata's model. Thus, the diagnostic characteristics of a functional m-redundant system is analyzed by the methods originated by Preparata et al..

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.22 no.6
• /
• pp.599-609
• /
• 2021

A novel grounding system, which is presented in IEC 60364, has been adopted since 2021. A safety evaluation for the human body on the grounding system is required due to the various characteristics of the touch voltage and current passing when the human body experiences an electric shock. The Korea Electrical Safety Corporation (KESCO) and Korea Electric Association (KEA) have been conducting a safety technical education on the grounding system. On the other hand, it is difficult to instruct the electrical safety manager because of a lack of safety evaluations for the test equipment on the grounding system. Therefore, this paper modeled and implemented a test device for a safety evaluation depending on the grounding system of IEC 60364. Namely, this paper presents the modeling of the test device for a safety evaluation using PSCAD/EMTDC S/W, which is composed of an AC grid section, s test device section on the grounding system, and a sub-device section. This paper implemented a test device for safety evaluation, which consisted of an AC grid section, TT grounding system section, TN-S grounding system section, and monitoring section. From the simulation and test results with the safety characteristics of the human body in the TT and TN-S grounding system, when the fault impedances are 0[Ω], 10[Ω], and 100[Ω], the currents passing through the human body in the TT grounding system are 104[mA], 87.4[mA], and 35.5[mA], respectively. The corresponding currents in the TN-S grounding system are 54.9[mA], 4.1[mA], and 0.4[mA], respectively. Based on the results, the protection performance for an electric shock to the human body in the TN-S system is better than the TT system. This can be improved when the existing grounding system is changed from the TT system to the TN-S system.

• Proceedings of the KSR Conference
• /
• 2007.05a
• /
• pp.280-288
• /
• 2007

This paper is based on the safety case as specified in the E&M system safety management plan established in initially AREX project. The safety case for E&M system is the synthesis of all safety activities throughout the design, manufacturing, installation and commissioning test for E&M system. The safety level of E&M system which is required by E&M contract is assured by accomplishment of safety activities and procedures in accordance with EN standards.

• Journal of Aerospace System Engineering
• /
• v.12 no.5
• /
• pp.48-53
• /
• 2018

In this study, Real-Time Operating System(RTOS) and 3-D collision avoidance algorithm are implemented to three different Miciro Controller Unit(MCU)s and their performances compared. We selected Microchip Technology's ATmega2560, STM's ARM Cortex-M3 and ARM Cortex-M4, because they are widely used. FreeRTOS, an open-source operating system, was also used. The 3D collision avoidance algorithm consists of the vertical and the horizontal avoidance algorithm, which is implemented using C++. The performances of the MCUs were compared with respect to used memory and calculation time. As a result, Cortex-M4's calculation time was the fastest and ATmega2560 used least memory.

• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.2147-2150
• /
• 2003

Recently, many technologies of the P.L.C (Power Line Carrier) are introduced for an efficient communication. P.L.C communication sends information in the carrier signals by conduction over the power wire. An arc detector is proposed in this paper for the effective transmission. The Power Line Carrier has an advantage in low cost because it uses existent power line. It can be easily applied anywhere that a power line socket is available. But the P.L.C. is very noisy, because many electronic devices in generate electronic noise in modulated signals. This problem should be considered carefully in the design of the arc detector system using P.L.C in railway. The proposed system can be applied for monitoring the arc detector system and the arc locator system in railway. Hence the system will be able to exchange the arc information to be T.C.M.S. (Train Control Management System), bogies and even between a station and trains in railway and use to suspicion fire in train.

• Journal of Korean Institute of Industrial Engineers
• /
• v.39 no.6
• /
• pp.450-460
• /
• 2013

A complex system such as defense systems is in a form of System of Systems (SoS) in which each component is a system being independent of other component systems. Dynamical behavior of SoS is represented by a composition of behaviors of component systems. Thus, a M&S tool/environment would not be efficient for development of heterogeneous models nor for simulation in a centralized environment. Moreover, such an environment restricts reusability and composability. This paper presents an interoperation method for M&S of defense systems as SoS. The approach first develops component system models using tools, each specialized to M&S of each component system. It then interoperates such simulations together to simulate a whole system as SoS. HLA/RTI is employed for such interoperation, which is a DoD/IEEE standard to support interoperation. We will introduce a case study for interoperable simulation of defense systems, which consists of a wargame simulator and a communication simulator.

• Korean Journal of Optics and Photonics
• /
• v.4 no.1
• /
• pp.15-21
• /
• 1993

This paper describes the design and development of a KrF excimer laser stepper and discusses the detailed system parameters and characterization data obtained from the performance test. We have developed a deep UV step-and-repeat system, operating at 248 nm, by retrofitting a commercial modules such as KrF excimer laser, precision wafer stage and fused silica illumination and 5X projection optics of numerical aperture 0.42. What we have developed, to the basic structure, are wafer alignment optics, reticle alignment system, autofocusing/leveling mechanisms and environment chamber. Finally, all these subsystem were integrated under the control of microprocessor-based controllers and computer. The wafer alignment system comprises the OFF-AXIS and the TTL alignment. The OFF-AXIS alignment system was realized with two kinds of optics. One is the magnification system with the image processing technique and the other is He-Ne laser diffraction type system using the alignment grating on the wafer. 'The TTL alignment system employs a dual beam inteferometric method, which takes advantages of higher diffraction efficiency compared with other TTL type alignment systems. As the results, alignment accuracy for OFF-AXIS and TTL alignment system were obtained within 0.1 $\mu\textrm{m}$/ 3 $\sigma$ for the various substrate on the wafers. The wafer focusing and leveling system is modified version of the conventional systems using position sensitive detectors (PSD). This type of detection method showed focusing and leveling accuracies of about $\pm$ 0.1 $\mu\textrm{m}$ and $\pm$ 0.5 arcsec, respectively. From the CD measurement, we obtained 0.4 $\mu\textrm{m}$ resolution features over the full field with routine use, and 0.3 $\mu\textrm{m}$ resolution was attainable under more strict conditions.

• Journal of the Korean Mathematical Society
• /
• v.46 no.5
• /
• pp.1087-1103
• /
• 2009

Given a system of s independent 1-forms on a smooth manifold M of dimension m, we study the existence of integral manifolds by means of various generalized versions of the Frobenius theorem. In particular, we present necessary and sufficient conditions for there to exist s'-parameter (s' < s) family of integral manifolds of dimension p := m-s, and a necessary and sufficient condition for there to exist integral manifolds of dimension p', p' $\leq$ p. We also present examples and applications to complex analysis in several variables.

• Applied Chemistry for Engineering
• /
• v.3 no.2
• /
• pp.189-193
• /
• 1992

The success of 3M's worldwide Pollution Prevention Pays (3P) Program convinced 3M's top management that the program should be expanded into a comprehensive environmental management system called 3P Plus. The emphasize of the 3P Plus program is to continually minimize the environmental impact of 3M processes, products, and operations to include energy management, resource recovery, and other initiatives. 3M's experience with the 3P and 3P Plus programs will be described. 3M's experience can serve as a model for other multi-national companies interested in sustainable development and economic growth with environmental protection.