• The KIPS Transactions:PartB
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• v.14B no.6
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• pp.401-406
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• 2007

This study discusses the development of a u-Health care system that can detect quickly and cope actively with emergent situations of chronic disease patients who lead everyday life. If a patient's emergent situation is detected by personal health care host(PHCH), which is composed of acceleration and vibration sensors, GPS, and CDMA communication module, a text message on the patient's current location is transmitted to the hospital and the guardian's mobile terminal so that they can cope with the situation immediately. Especially, the system analyzes data from sensors by using neural network and determines emergent situations such as syncope and convulsion promptly. The exact location of patients can also be found in the electronic map by using GPS information. The experiments show that this system is very effective to find emergencies promptly for chronic disease patients who cannot take care of themselves and it is expected to save many lives.

• Korean Journal of Microbiology
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• v.38 no.3
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• pp.198-204
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• 2002

Poliovirus is a member of enterovirus which causes paralytic poliomyelitis, encephalitis and aseptic meningitis. Since poliovirus is spread by the fecal-oral route and poliovirus-contaminated water could be a potential threat for public health, detection of poliovirus in drinking water resource is important. Infectious poliovirus and poliovirus inactivated by heat or UV were used to test three detection methods such as cell culture method, reverse transcription-polymerase chain reaction (RT-PCR) and integrated cell culture (ICC)-PCR. Infectious poliovirus was detected by all three methods and ICC-PCR was the most sensitive and fast in detecting poliovirus. Inactivated polioviruses could not be detected by cell culture or ICC-PCR methods. On the other hand, heat- inactivated viruses could be detected by RT-PCR. Thus it is suggested that ICC-PCR method is the most sensitive and effective in detecting infectious polioviruses in water sample.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.11
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• pp.4087-4094
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• 2010

The sensor data which is measured by Quadruped robot is utilized to recognize the physical environment or other information and to control the posture and walking of robot system. In order to control the robot precisely, high accuracy of sensor data is required, most of these sensors however, belongs to expensive and low-durable products. Moreover, these are exposed excessive load operation in a field condition if it is applied to field robot system. This issue becomes more serious one when the robot system is manufactured as a mass product. As in this context, this study suggests a virtual sensor technology to alternate or assist the main sensor system. This scheme is realized by using back-propagation algorithm of neural network theory, and the quality of estimated sensor data could be improved through the algorithmic and hardware based treatments. This study performs the various trial to identify the effective parameters which effect to the quality and reliability of estimated sensor data and tries to show the possibility of proposed methodology.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.7
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• pp.767-777
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• 1999

인과적 메시지 로깅 기법은 정상프로세스를 역전(roll-back)시키거나 메시지의 저장을 위해 프로세스의 수행을 중단시키지 않는 장점을 지니고 있지만, 메시지의 크기가 지나치게 커진다는 단점을 지니고 있다. 본 논문에서는 인과적 메시지 로깅 기법의 이러한 문제점을 해결하기 위하여 로그 상속의 개념을 정의하고 로그 연혁을 이용하여 로그 비용, 특히 로그 크기 면에서 효율적인 로깅 기법을 제안한다. 또한 이 로깅 알고리즘을 이용하여 복구시 메시지의 수와 크기를 줄여 복구시간을 줄이는 효율적인 복구 알고리즘을 제안하고, 제안한 알고리즘이 메시지 로그 크기 면에서 효율적임을 증명한다. 또 제안한 알고리즘의 성능을 검증하기 위하여 두 가지 종류의 모의 실험을 수행하여 기존의 로깅 프로토콜과 메시지 크기 면에서의 성능을 비교한 결과를 제시하였다.Abstract Causal message logging has many good properties such as nonblocking message logging and no rollback propagation. However, it requires a large amount of information to be piggybacked on each message, which may incur severe performance degradation. This paper presents an efficient causal logging algorithm based on the new message log structure, LogOn, which represents the causal inter-process dependency relation with much smaller overhead compared to the existing algorithms. The proposed algorithm is efficient in the sense that it entails no additional information other than LogOn to be carried in each message, while other existing algorithms require extra information other than the message logs. This paper also presents an efficient recovery algorithm to solve the problem of a large amount of data exchanges during the recovery. To verify the performance of our algorithm, we give an analysis of the algorithm and perform two simulations and compare the log size with other causal logging protocols.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.11
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• pp.2143-2149
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• 2007

Visual Cortex Stimulator is among artificial retina prosthesis for blind man, is the method that stimulate the brain cell directly without processing the information from retina to visual cortex. In this paper, we propose image construction and recognition model that is similar to human visual processing by recognizing the feature data with orientation information, that is, the characteristics of visual cortex. Back propagation algorithm based on Delta-bar delta is used to recognize after extracting image feature by Kirsh edge detector. Various numerical patterns are used to analyze the performance of proposed method. In experiment, the proposed recognition model to extract image characteristics with the orientation of information from retinal cells to visual cortex makes a little difference in a recognition rate but shows that it is not sensitive in a variety of learning rates similar to human vision system.

• Korean Journal of Remote Sensing
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• v.15 no.3
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• pp.183-194
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• 1999

The Brightness, color and texture included in a multispectral satellite data are used as important factors to analyze and to apply the image data for a proper use. One of the most significant process in the satellite data analysis using texture or color information is to extract features effectively expressing the information of original image. It was described in this paper that six features were introduced to extract useful features from the analysis of the satellite data, and also a classification network using the back-propagation neural network was constructed to evaluate the classification ability of each vector feature in SPOT imagery. The vector features were adopted from the training set selection for the interesting region, and applied to the classification process. The classification results showed that each vector feature contained many merits and demerits depending on each vector's characteristics, and each vector had compatible classification ability. Therefore, it is expected that the color and texture features are effectively used not only in the classification process of satellite imagery, but in various image classification and application fields.

• Journal of Adhesion and Interface
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• v.22 no.4
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• pp.153-157
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• 2021

Graphene, a two-dimensional carbon allotrope, has outstanding mechanical and electrical properties. In particular, the charge carrier mobility of graphene is known to be about 100 times higher than that of silicon, and it has received attention as a core material for next-generation electronic devices. However, graphene is very sensitive to environmental conditions, especially vulnerable to moisture or oxygen. It becomes a disadvantage in that the stability of the graphene-based electronic device, so various attempts are being made to solve this problem. In this work, we report a method to greatly improve the stability by controlling the surface energy of the polymer layer used for transferring the insulating layer of the graphene field-effect transistor. As the surface energy of the polymer used as the insulating layer was lowered, the stability could be improved by effectively controlling the adsorption of impurities in the atmosphere such as water molecules or oxygen.

• Journal of IKEEE
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• v.23 no.3
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• pp.785-792
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• 2019

In parallel operation of multiple power converter modules, equal power distribution among modules shall be made to improve the reliability of the system. In this paper, a novel droop method is proposed to present improved current distribution characteristics. In the proposed method, if the current in each module become greater than the current set-point value, the output voltage set-point is raised to improve the current distribution characteristics. Meanwhile, when the output voltage is to be managed within the tolerance range, the range of the usable control IC reference value ($v_{ref}$) will be reduced if the output voltage setting is always raised. Thus, in case the output voltage set-point among modules is reversed, the downward adjustment is introduced. The proposed method was experimentally validated with a 17.5V/500mA prototype of two boost converters operating in parallel.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.6
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• pp.1045-1054
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• 2020

In this paper, we designed a TCP/IP based ring buffer system that can stably transfer bulk data streams in the unstable network environments. In the scheme we proposed, The observation data stream generated and output by each radio observatory's backend system as a UDP frame is stored as a UDP packet in a large capacity ring buffer via a socket buffer in the client system. Thereafter, for stable transmission to the remote destination, the packets are processed in TCP and transmitted to the socket buffer of server system in the correlation center, which packets are stored in a large capacity ring buffer if there is no problem with the packets. In case of errors such as loss, duplication, and out of order delivery, the packets are retransmitted through TCP flow control, and we guaranteed that the reliability of data arriving at the correlation center. When congestion avoidance occurs due to network performance instability, we also suggest that performance degradation can be minimized by applying parallel streams.

• Journal of Convergence for Information Technology
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• v.11 no.8
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• pp.1-7
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• 2021

In this paper, a method of extending 1 bit by adding an external device to a parallel interface type Digital-to-Analog conversion(D/A C) circuit is presented. To do this, the principle of the D/A C circuit was examined, and the problems that occur when extending one bit by adding individual devices were analyzed, and a bit extension method of the D/A devices using an OP-Amp. circuit was presented. As the proposed method uses the high-precision characteristics of the OP-Amp., even if an error occurs in the device, only the overall size of the output waveform is affected, and the voltage reversal phenomenon that occurs between each bit does not occur. In order to confirm the effect of the proposed method, an experimental circuit was constructed and the absolute voltage of the output and the relative error were measured. As a result, a voltage error of 0.0756% appeared, confirming that the 0.195% requirement for one bit expansion by adding individual devices was sufficiently satisfied.