• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.5
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• pp.2481-2486
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• 2013

It requires a lot of time and effort for general users who do not have enough understanding of GPS to properly processing GPS data. However, the GPS data processing field heavily relies on foreign-produced software and there is almost no development of user-oriented technology. Therefore, in this study, it was attempted to build an expert service that enables non-experts to use high-precision GPS data processing. As a result, an expert service that can maximize user convenience simply by entering the minimum required information for GPS data processing was developed, and the expert service was verified by relative positioning processing of the observation data of satellite control point provided by National Geographic Information Institute and observation data obtained by GPS survey. The expert service significantly reduces the effort and time for processing GPS data, which will contribute to precise positioning and other various studies.

• The Transactions of the Korea Information Processing Society
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• v.7 no.9
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• pp.2940-2947
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• 2000

In the wireless ATM networks, a Medium Access Control (MAC) protocol is required to support an integrated mix of multimedia traffic services. The MAC protocol should be designed in a way that the limited wireless bandwidth can be efficiently utilized maximizing the Quality of Service (QoS) guarantees for various traffic service classes. In this paper, a Dynamic Resource Allocation-based MAC protocol, which satisfies QoS of each traffic service class in the wireless ATM environment, is proposed. The proposed MAC protocol adopts the dynamic channel allocation schemes for a mix of different traffic service classes. The suggested MAC protocol is designed to provide the QoS guarantees for Constant Bit Rate (CBR) or real-time Variable Bit Rate (VBR) traffic through fixed or dynamic reservation. For Available Bit Rate (ABH) traffic, which has the lowest priority among the traffic classes, large improvement in delay by reserving the minimum bandwidth is shown. And for real-time VBR traffic, increase in throughput of transmission is demonstrated because of bandwidth, which is allocated through contention at the initial phase and without contention thereafter.

• Journal of Advanced Navigation Technology
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• v.22 no.1
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• pp.37-42
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• 2018

Recently, there have been many studies on the IoT environment in which the sensors attached to the equipment automatically transmit and process the site information in real time through the network to control the equipment. The core of such a system is a network for data transmission and reception, and a wired network with wide transmission distance is a priority. However, in the case of a wired network, there is a problem that the time and cost consumed to configure the communication is higher than that of the wireless. In this paper, we propose LPWA - based wireless data transmission system using LPWA and BLE communication to solve this problem. The proposed system collects data from equipment through BLE and transmits data to the server using LPWA. Experimental results show that the spreading factor of maximum length of LPWA is 8, and the minimum length is 9.

• Journal of the Korea Society of Computer and Information
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• v.19 no.12
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• pp.187-196
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• 2014

In this paper, Minimize driving energy for operation within a defined distance yeokgan fixed time-resolved and determine the nature of the train is traveling, and to model mathematically. Urban rail car cruise in general by the PID controller is used instead of automatically tracking a target value while traveling in energy consumption to be minimized by using optimal control model railroad charyangreul was designed under real operating conditions the same. The actual track conditions apply to the minimum value or a separate listing of cars around the track facility without a driving energy of the automatic operation and to reduce the driving energy. Therefore, actual route chosen straight line 8 / gradient segment / curve for the measured data analysis, such as sections within the city-minute drive each section and presented how the trains to save energy, depending on the pattern of the train station in the region.

• Journal of Photoscience
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• v.11 no.32
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• pp.55-59
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• 2004

The present investigation is an attempt to create an optimized protocol for a bactericidal modality of different powers of He-Ne laser radiation to eliminate periodontitis disease causing bacteria from dental plaques. Periodontitis is most prevalent infectious disease of men and caused by a limited number of Gram negative oral bacteria. Porphyromonas gingivalis and Streptococcus sanguis are the important bacteria responsible for periodontitis diseases. Effect on periodontitis disease causing bacteria were produced by the exposure of different powers of He-Ne laser light i.e. 9 mW, 17 mW and 26 mW of red colour of wavelength 632.8 nm in two different periods of time i.e. 10 min. and 20 min. in the presence of dye Methylene blue (MB) used as a photosensitizer. The results have been shown in terms of percentage inhibition of colony forming units (cfu.) of bacteria. This study has shown that maximum inhibition of cfu. were observed in Laser+MB-20 min. exposure time. This inhibition was followed by Laser+MB-10 min., but minimum inhibition was seen in Laser only at 10 min. exposure. In case of effect of methylene alone on the cfu. of bacteria, it was seen that MB have not shown more inhibition of cfu. and it had shown that the no. of cfu. are very similar to that of control. The above observation of the present study was seen in case of every 3 different type of used powers of laser for both the bacteria. Maximum percentage inhibition of cfu. were seen in case of 26mW powers of He-Ne laser, which was 67. 28% to 61.42% for Porphyromonas gingivalis and Streptococcus sanguis respectively. So, increasing the power of laser (safe range for dentistry is 3-30 mW) under conditions shows an increased percentage inhibition of cfu. Thus the present investigation may be a useful adjunct with mechanical debridement in the prevention of recolonization of subgingival lesions by pathogenic microorganisms which are harmful and drug resistant.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.1
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• pp.45-52
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• 2018

In this paper, we propose smart digital door lock system using heterogeneous communication. This system has efficient function using RF communication and Internet communication, and realizes access and real image of the passengers by combining camera control technology to secure original competitiveness with existing products. It uses the Internet of things and receive images to and from your smart-phone. And senses human behavior. In the simulated results, the image transmission rate of 90 % or more and the time required to transmit 10,000 images have an average transmission speed of 3 seconds. It is expected to secure competitiveness to increase the security of door lock in the future by enabling minimum security and fire monitoring service in real time.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.2
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• pp.179-184
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• 2017

Due to rapid development of infrared guided weapon, survivability of armored vehicle is severely threatened. Hence, reduction of susceptibility by lowering infrared signature level is essential to enhance survivability of the vehicle. For this purpose, numerical analysis is conducted to analyze time and spatial characteristics of infrared signature of the vehicle when surface emissivity changes in this study. The analysis shows that the emissivity which produces minimum contrast radiant intensity is significantly altered by time and detecting position. Based on the result, it is concluded that the controlled structures which have different emissivity should be adopted at different region of the vehicle to effectively decrease infrared signature level.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.10 s.340
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• pp.39-50
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• 2005

In this paper, we propose a performance improving MAC algerian for the IEEE 802.11 DCF. WLAN based IEEE 802.11 uses two control methods called 'Distributed Coordination Function(UF)' and 'Point Coordination Function(PCF)'. The nF controls the Urnsmission based on carrier sense multiple access with collision detection(CSMA/CA), that decides a random backoff time with the range of contention window for each terminal. Normally, each terminal the CW double after collision, and reduces the CW to the minimum after successful transmission. This paper proposes an enhanced DCF algorithm that decreases the CW smoothly after successful transmission in order to reduce the collision Probability by utilizing the current status information of WLAN. We also analyze the throughput and delay performance for the unsaturated case mathematically. Simulation results show that our algorithm enhances the saturation throughput of WLAN. They also coincide well with the analytical results.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.19 no.1 s.71
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• pp.47-54
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• 2006

In this study, an optimum support design problem is considered to minimize displacement of stacked plates under self weight condition. During the displacement analysis, several kinds of contact arise between the plates themselves and support bar. These can be easily considered if commercial analysis software, which provides capability to solve the contact problem, is used. It is found, however, that the computing time is extraordinarily long due possibly to the generality of the software and also to the ignorance of the control parameters used in the software. In this paper, the contact condition is imposed directly by the authors, while the software is used only to solve the ordinary displacement analysis problem. In this way, the computing time is decreased remarkably by more than 30 times, while yielding the same accurate results. Optimization is conducted based on this efficient analysis method to find minimum number of supporting bars using the response surface algorithm.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.216-227
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• 2005

The head penetrations for control rod drive mechanism and instrumentation systems are installed at the reactor pressure vessel head of PWRs. Primary coolant water and the operating conditions of PWR plants can cause cracking of these nickel-based alloy through a process called primary water stress corrosion cracking (PWSCC). Inspection of the head penetrations to ensure the integrity of the head penetrations has been interested since reactor coolant leakages were found at U. S. reactors in 2000 and 2001. The complex geometry of the head penetrations and the very low echo amplitude from the fine, multiple flaws due to the nature of the see made it difficult to detect and size the flaws using conventional pulse-echo UT methods. Time-of-flight-diffraction technique, which utilizes the time difference between the flaw tips while pulse-echo does the flaw response amplitude from the flaw, has been selected for this inspection for it's best performance of the detection and sizing of the head penetration see flaws. This study defines the limits of the detectable and accurately sizable minimum flaw size which can be detected by the General TOFD and the Delta TOFD techniques for circumferentially and axially oriented flaws respectively. These results assures the reliability of the inspection techniques to detect and accurately size for various kind of flaws, and will also be utilized for the future development and qualifications of the TOFD techniques to enhance the detecting sensitivity and sizing accuracy of the flaws of the reactor head penetrations in nuclear power plants.