• Journal of Korean Society of Industrial and Systems Engineering
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• v.17 no.32
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• pp.53-62
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• 1994

This paper deals with the analysis of the PC communication service system performance which will be installed as a gateway between PSTN and PSDN. Firstly, we classify the data traffic pattern into interactive, conversational, and file transfer type from the actual statistics. Secondly, we model the system structure as a closed queueing network model with multiservers and multiple customer classes and derive the analytic method to be able to measure the system performance using Mean Value Analysis. Finally, the simulation results indicate that the analytic method obtained is a good approximation method to measure the system performance of the PC communication service system as a gateway between PSTN and PSDN.

• Clean Technology
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• v.23 no.3
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• pp.248-255
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• 2017

In dismantling factories for recycling, it is important to input actual working data to a personal computer (PC) in order to monitor the work results and related recycling rate of the inputs. This should be performed with a keyboard, a mouse, or other devices. But when a worker is working in the factory, it could be bothersome or time consuming to go to the PC. Especially, workers who works at dismantling factories have a generally low education level are scared to use a PC, which could be used as a pretext for not using the PC. In some cases, data input is performed by a worker after the day's job. In this case, it could take additional time, the worker can make more mistakes, and the data could be unreliable. In this study, we developed a man-machine interface (MMI) device using a safety helmet. A joystick-like device, pushbuttons, and a radio frequency (RF) device for wireless communication is equipped in a safety helmet. This MMI device has functions similar to a PC mouse, and it has a long communication distance. RF is used because it consumes less battery power than Bluetooth. With this MMI device, workers need not go to a PC to input data or to control the PC, and they can control the PC from a long distance. The efficiency of PCs in a factory could be increased by using the developed MMI system, and workers at the dismantling factories could have less reluctance in using the PC.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.11
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• pp.635-642
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• 2004

The traditional communication protocols such as TCP/IP are not suitable for PC cluster systems because of their high software processing overhead. To eliminate this overhead, industry leaders have defined the Virtual Interface Architecture (VIA). VIA provides two different data transfer mechanisms, a traditional Send/Receive model and the Remote Direct Memory Access (RDMA) model. RDMA is extremely efficient way to reduce software overhead because it can bypass the OS and use the network interface controller (NIC) directly for communication, also bypass the CPU on the remote host. In this paper, we have implemented VIA-based RDMA mechanism in hardware. Compared to the traditional Send/Receive model, the RDMA mechanism improves latency and bandwidth. Our RDMA mechanism can also communicate without using remote CPU cycles. Our experimental results show a minimum latency of 12.5${\mu}\textrm{s}$ and a maximum bandwidth of 95.5MB/s. As a result, our RDMA mechanism allows PC cluster systems to have a high performance communication method.

• Journal of the Korean Institute of Intelligent Systems
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• v.13 no.6
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• pp.698-703
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• 2003

This paper presents analog secure communication system about safe speech transmission using chaotic signals. We applied various conditions that happen in actuality communication environment modifying chaotic synchronization and chaotic communication schemes and analyzed restoration performance of speech signal to computer simulation. In transmitter, we made the chaotic masking signal which is added voice signal to chaotic signal using PC(Pecora ＆ Carroll) and SFB(self-feedback) control techniques and transmitted encryption signal to noisy communication channel And in order to calculate the degree of restoration performance, we proposed the definition of analog average power of recovered error signals in receiver chaotic system. The simulation results show that feedback control techniques can certify that restoration performance is superior to quantitative data than PC method about masking degree, susceptibility of parameters and channel noise. We experimentally computed the table of relation of parameter fluxion to restoration error rate which is applied the encryption key values to the chaotic secure communication.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.7-12
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• 2005

In this paper, we implemented an e-mail and chat program (client) for communication between mobile devices and PCs based on WIPI a South Korea's open wireless platform form developing device and content independent software to break from the way of developing contents that is dependent on different wireless platforms to each mobile communications company. While traditional e-mail and chat programs are written for PC-to-PC communication, we develop them for mobile-to-PC and mobile-to-mobile communications, and we expect to see various mobile contents in the future.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.4
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• pp.71-78
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• 2015

Since most education organizations such as Universities have a plenty of PCs, much electric power can be wasted if their power states are not managed properly. This paper introduces the RPM(Remote Power Management) software system implemented to reduce a waste of PC power in Universities. The System manager can monitor power state of all PCs in a University and turn off PCs or change power states of PCs to low power states. The RPM consists of three software modules. First, Power Controller, which is installed in each user PC, saves the power by changing low power state by utilizing low power algorithm proposed in this paper. Also it reports power state of its PC to Power Server on the state changed. Second, Power Server module gathers power state information of all PCs, stores them in a DB, and sends all or some parts of the information to Power Viewer whenever the manager asks. The manager can turn off or change a certain PC to low power state. We evaluated the performance of power saving for the RPM and the result showed achievement of 40% power saving.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2892-2894
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• 2000

인터넷을 이용한 원격 제어에 있어서는 통신 프로토콜은 TCP/IP를 기반으로 이루어지고 있는데 대개의 경우는 소켓을 이용한 PC기반에서 해석되어 지고 처리되어 진다. 본 논문에서는 PC기반의 원격제어 시스템을 임베디드화함으로써 시스템의 안정성과 속도면에서 우수한 시스템을 구현하려고 한다. 이를 위하여 임베디드 시스템은 HD860-R3보드를 이용하였고 실시간 운영체제로 리눅스를 사용하였다 실질적인 제어물의 제어를 위해서 제어기를 설계 HD860-R3보드와 시리얼을 통하여 통신하였다. 나아가 이 시스템을 PC기반의 시스템에서 탈피한 시스템을 홈 오토메이션의 제어 시스템에 적용시켜 보려 한다.

• Journal of the HCI Society of Korea
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• v.7 no.2
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• pp.35-42
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• 2012

The purpose of this study was to evaluate the usability of the tablet PC-based Korean high-tech AAC(Augmentative Alternative Communication System) software. In order to develop an AAC software which is appropriate to Korean cultural/linguistic contexts and communication needs of the users, we examined the necessity and ease of use for the communication functions that are required in native Korean communication, such as polite expressions, tense expressions, negative expressions, subject-verb auto-matching, and automatic sentence generation functions, using a scenario-based user testing. We also investigated the users' needs, preferences, and satisfaction for the tablet PC-based Korean high tech AAC using a semi-structured and open questionnaires. The participants of this study were 9 special education teachers, 6 speech therapists, and 6 parents whose children had communication disabilities. The results of the usability testing of the tablet PC-based Korean high-tech AAC software presented positive responses in general, by indicating overall scores of above 4 out of 5 except in tense and negative expressions. The necessity and ease of use in the tense and negative expressions were evaluated relatively low, and it might be related to the inconsistent interface with the polite expressions. In terms of the user interface(UI), there were users' needs for clear visual feedback in the symbol selection and display, consistent interface for all functions, more natural subject-verb auto-matching, and spacing in the text within symbols. The results of the usability testing and users' feedback might serve as a guideline to compensate and improve the function and UI of the existing AAC software.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.138-138
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• 2008

In this study, effect of thickness on structural, electrical and optical properties of B doped ZnO:Al (AZOB) films was investigated. AZOB films were deposited on PC substrates by DC magnetron sputtering. The thickness range of films were from 300 nm to 800 nm to identified as increasing thickness, stress between substrate and AZOB film. The. average transmittance of the films was over 80 % until 500 nm. Then a resistivity of $1.58\times10^{-3}\Omega$-cm was obtained. We presented that a AZOB film of 500 nm was optimization to obtain a high transmittance and conductivity.

• Journal of the Korean Graphic Arts Communication Society
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• v.16 no.3
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• pp.43-60
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• 1998

The photosensitive properties and spectroscopic characteristics in the organic photoconductor(OPC) with carrier generation layer(CGL) of poly(vinylbutyral)(PVB) and polycarbonate(PC) doped with titanyl phthalocyanine(TiOPc) were investigated. The change of crystal structure of TiOPc dispersed with PVB and PC was shown by UV-visible reflective spectrum and FT-IR spectrum and mainly caused by the difference of solubility of solvent and the interaction between TiOPc and binder. The particle size of TiOPc dispersed with PVB measured by SEM was smaller than in PC. The crystal structure of TiOPc dispersed with PVB was amorphous type and in PC was $\alpha$type. It was found that the photosensitive properties of OPC were dependent on the change of absorbance and ionization potential of TiOPc occurred from the difference of crystal structure. In this work, the photosensitivity of OPC of TiOPc dispersed with PVB was better than PC due to the crystal type and the smaller particle size.