• Journal of the Korea Society of Computer and Information
• /
• v.27 no.6
• /
• pp.117-122
• /
• 2022

In this paper, we developed a vehicle control terminal using IoT and low-power long-distance communication (NB-IoT) technology. This system collects information on the location and status of a parked vehicle, and transmits the vehicle status to the vehicle owner's terminal in real time with low power to prevent vehicle theft, and in the case of a vehicle in motion, When primary information about the vehicle, such as an impact, is collected and transmitted to the server, the server analyzes the relevant data to generate secondary information on traffic congestion, road damage, and safety accidents. By sending it, you can know the exact arrival time of the vehicle at its destination. This terminal device is an IoT gateway for a vehicle and can be connected to various wired and wireless sensors inside the vehicle. In addition, the data collected from vehicle maintenance, efficient operation, and vehicles can be usefully used in the private or public sector.

• Journal of The Korean Association of Information Education
• /
• v.8 no.1
• /
• pp.91-99
• /
• 2004

According to get ubiquitous environment, it is suggested to environment to get information with whichever terminal at any time wherever. Advancement of ability of mobile device increase requirement of wireless internet base solution. In this paper We developed distance education system based on wireless internet. This system has no problem of bandwidth and resolution of pocket pc because of using SWF(Shockwave Flash). It can maintain readability of high quality when size of resolution is changed but another graphic format can't maintain it.

• Proceedings of the KIEE Conference
• /
• 2001.11b
• /
• pp.333-335
• /
• 2001

In this paper, an algorithm for fault location in Auto Transformer(AT) Feeding Railway system is presented. If a fault occurs at the AT feeding circuits of electrical railway system, it is very important to find fault location and to remove it immediately for the purpose of ensuring safety for transportation. Because the characteristics of reactance-distance are not linear, only using one terminal signals to give fault distance is difficult. In this paper, first, using the KVL, 4 voltage equation are obtained. Secondly, eliminating voltage a distance equation which consists of currents at rail and line parameters including mutual effects.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.27 no.7
• /
• pp.89-94
• /
• 2013

This paper presents a method of simulating the protection effects of surge protective devices(SPDs) depending on the protective distance and types of input impedance of load to be protected. In order to analyze the protective performances of voltage-limiting type SPDs associated with the reflection and oscillation phenomena, the terminal voltage across load being protected and the residual voltage of SPDs were simulated by using EMTP model as functions of the protective distance and types of input impedance of loads. As a consequence, SPDs should be installed by taking into account the protective distance and input impedance of loads to achieve reliable protection of electrical and electronic equipment from lightning and switching surges. It is expected that the simulation method proposed in this paper could be practically used in design for installing SPDs in low-voltage distribution systems.

• The Journal of Korean Academic Society of Nursing Education
• /
• v.29 no.1
• /
• pp.60-71
• /
• 2023

Purpose: The purpose of this study was to identify changes in the experience rate and level of symptoms of visual display terminal syndrome in college students attending online classes during the COVID-19 pandemic. Methods: Data were collected from February 22 to June 8, 2021 at three measurement points. A total of 117 college students were administered a visual display terminal syndrome survey just before online classes (T1), one month after the start of online classes (T2), and three months after the start of online classes (T3). The collected data were analyzed by frequency and percentage, paired t-test, McNemar test, and repeated measures analysis of variance using the IBM SPSS 25.0 program. Results: The intensity of college students' visual display terminal syndrome during online classes increased at T2 and T3 compared to T1. The rate of experiencing back discomfort or pain increased abruptly at T2 compared to T1. The intensity of college students' eye related symptoms and skin related symptoms increased at T2 and T3 compared to T1, while the intensity of college students' psychological symptoms, general body discomfort, and musculoskeletal symptoms increased at T3 compared to T1. Conclusion: The results of this study suggest that self-care programs are needed to prevent visual display terminal syndrome in college students who are in long-term online classes.

• International Journal of Aeronautical and Space Sciences
• /
• v.18 no.4
• /
• pp.719-728
• /
• 2017

This paper proposes a synthesis of new guidance law to generate an evasive maneuver against enemy's missile interception while considering its impact angle, acceleration, and field-of-view constraints. The first component of the synthesis is a new function of repulsive Artificial Potential Field to generate the evasive maneuver as a real-time dynamic obstacle avoidance. The terminal impact angle and terminal acceleration constraints compliance are based on Time-to-Go Polynomial Guidance as the second component. The last component is the Logarithmic Barrier Function to satisfy the field-of-view limitation constraint by compensating the excessive total acceleration command. These three components are synthesized into a new guidance law, which involves three design parameter gains. Parameter study and numerical simulations are delivered to demonstrate the performance of the proposed repulsive function and guidance law. Finally, the guidance law simulations effectively achieve the zero terminal miss distance, while satisfying an evasive maneuver against intercept missile, considering impact angle, acceleration, and field-of-view limitation constraints simultaneously.

• The Journal of Korean Academic Society of Nursing Education
• /
• v.22 no.4
• /
• pp.485-494
• /
• 2016

Purpose: The present research is a descriptive study aimed at understanding clinical nurses' Video display terminal (VDT) syndrome and identifying the factors that affect their VDT syndrome. Methods: Data were collected from 239 clinical nurses working in two metropolitan cities. Research tools included subject's VDT syndrome assessing musculoskeletal, ophthalmic, dermal, psychiatric, and whole body syndromes. The data were analyzed using frequency analysis, average and standard deviation, t-test, One-way ANOVA, and multiple regression analysis with the SPSS/WIN 20.0 program. Results: The subjects' VDT syndrome score was 1.34 out of 5. There were significant differences in participating subjects' VDT syndrome, hospital's size, working unit, health status, diagnosis of illness, having an Order Communication System (OCS), having an Electronic Medical Record (EMR) System, continuous VDT working for more than one hour, break time during VDT use, VDT use time, comfort of the chair, adjustability of the height of the chair, size of the VDT's desk, distance between the monitor and the user's eyes, resolution of the monitor, and frequency of eye exercise during VDT use. According to the research, influencing factors on VDT syndrome in clinical nurses included size of the VDT's desk, frequency of eye exercise during VDT use, having an EMR system, break time during VDT use, diagnosis illness, and having an OCS' system. Conclusion: The findings from this study can be used as a basis for future VDT syndrome prevention education and programs for clinical nurses.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.14 no.3
• /
• pp.51-56
• /
• 2014

TETRA(TErrestrial Trunked RAdio) provide specialized disaster radio communication services as a standard European for digital TRS(Trunked Radio System). Especially, DMO(Direct Mode Operation) feature is used effectively in the radio shadow areas which base station does not propagate radio signal because it can communicate directly with terminal to terminal without base station's relay function. However, to effectively used DMO feature, radio coverage prediction information should be provided to users. Therefore in this paper, we were calculated link budget of TETRA DMO terminals which were distributing and operating in the country and then predicted reaching distance about radio propagation to be applied with path loss model.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.2 no.2
• /
• pp.117-130
• /
• 1999

In this paper, the performance of data communication function of military radio equipment P-999K is analyzed based on the standard CSMA/CA protocol which is DFWMAC standard protocol done by IEEE802.11 work group. Basic three standard protocols, i.e. Basic CSMA/CA, Stop & Wait ARQ and 4-Way Handshake CSMA/CA protocols are analyzed and compared with each other under the hidden terminal environment. The computer simulation is also done by using SIMSCRIPT II.5 which is popular software tool for an independent processing. The results show that p-persistent(with p=0.3) CSMA scheme is superior to non-persistent CSMA scheme with non-hidden terminal condition, but the performances of both schemes are almost same with hidden terminal situation. And the results of computer simulations are also showed that Basic CSMA/CA protocol is superior to the other protocols when the ratio of hidden terminals is below 10 % of total user population, however, with the above 20% hidden terminals environment and the higher offered traffic conditions the 4-Way Handshake CSMA/CA protocol shows the most superior performance.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.27 no.2
• /
• pp.238-246
• /
• 2024

Modern military operations rely heavily on broadband communication and data transmission. Recently, the rising use of intelligent unmanned technology necessitates more frequencies. Free-space optical(FSO) communication can offer high-data-rate communications with high security and no need for licensing. Therefore, the FSO communication holds significant interest and potential in the defense industry. In this paper, we present design of a FSO communication terminal taking Korean domestic weather conditions into account. The domestic atmospheric attenuation is analyzed using several models and two-year meteorological information for a city in Korea, and this analysis is utilized to design the FSO communication terminal. The design results were verified using an FSO communication test bed, and we achieved an Ethernet bandwidth of approximately 1.86 Gbps at a distance of 1.3 km with the optical amplifier output power of the test bed set to about 20 dBm.