• Proceedings of the Korea Inteligent Information System Society Conference
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• 2001.01a
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• pp.198-201
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• 2001

Recently the wireless-internet has been spreading extensively. People are spending a large part of their time gaining access to information using a mobile device. With the rapid growth of on-line Electronic Commerce, the use of mobile devices creates a new paradigm that provides users with location-independent real time service. Although this new paradigm does have some advantages, limited process speed, low bandwidth, the low battery capacity of mobile devices, and a high rate of wireless network errors causes many overhead expenses during service time with the server. In this paper, we suggest an autonomous service delivery system, which provides mobile agent capability to users that cannot maintain a connection. We have developed the system based on java mobile agent technology. Using this system, we can provide more effective service to users when the user is sending requirements for service through a mobile device that has limited resources. Furthermore we can manage the contact server dynamically when new services are added.

• Journal of Internet Computing and Services
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• v.2 no.1
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• pp.63-75
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• 2001

With the popularization of internet, its application fields are spreading out every industry parts, especially there are great change in marketing areas by the internet. One of them is shopping mall. Assembly PC of old method being sale shopping mall is not consider in compatibility of each devices, because of using the assembling method of it. In this paper, in order to their has not specific knowledge on computer and consider of a compatibility to each devices, our implemented shopping mall that on the provided convenience by using the on-line customer, M implemented intelligent agent can advise compatibility of each devices using Fuzzy value.

• The Journal of the Korea Contents Association
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• v.11 no.12
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• pp.543-551
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• 2011

Recently various handheld multimedia devices are spreading, and users want to share media contents across their own multiple devices. Conventional synchronization techniques for N-screen services can continuously play contents by switching from an initial device to a new device. In this case, even if a new device plays continuously contents, the initial device stops playing them. In this paper, we propose a synchronization technique in which multiple devices can share and continuously play same contents simultaneously by gathering and passing URI and current play-time of the contents. The proposed synchronization technique is built on UPnP and DLNA, and tested by implementing a wireless home media network system.

• Journal of Satellite, Information and Communications
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• v.8 no.4
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• pp.70-74
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• 2013

In recent days, the number of users having multiple devices according to time and places continue to increases with the help of wide spreading plurality of mobile devices. Consequently, the need for a user to share a media content on his/her multiple devices; furthermore, this movement brings the expansion of N-screen service focusing on connectivity, mobility, and integrity. N-screen service is platform that mediates the use of content or services on multiple devices with the continuous playing scheme. However, N-screen services have the problem of being provided exclusively by a service provider. This paper aims to implement a continuous playing scheme based on RESTfull and on an open service platform; the prototype was successfully implemented on the Android - PC environment.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.231-232
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• 2022

Metaverse refers to a digitally expanded world by combining real and virtual spaces. As reality expands into the digital world, various things that were not possible before are possible with the aid of the system, and its usefulness is spreading metaverse rapidly regardless of industry. In particular, it is relatively easier to display information from the virtual world over the real world than to bring information from the real world into the virtual world, which is why most industries are pursuing a metaverse using AR(Augmented Reality). The construction industry also tried to introduce the AR metaverse except in certain fields such as education, but it is being used only limitedly due to the limitations of AR devices. The disadvantages of AR devices, which are sensitive to afterimage effects, narrow viewing angles, and environmental influences, are the main reasons that make AR challenging to use in actual workplaces, not only in the construction industry but also in other industries. So as the technological maturity of VR(Virtual Reality) devices increases, VR will gradually replace AR. Therefore, in response to future changes, the construction industry should plan metaverse technology development using VR devices.

• Journal of Mechanical Science and Technology
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• v.18 no.4
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• pp.681-688
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• 2004

For use of the thermal cycle of the biochemical fluid sample, the isothermal temperature source with a large surface area was designed, fabricated and its thermal characterization was experimentally evaluated. The comprehensive overview of the technology trend on the temperature control devices was detailed. The large surface area isothermal temperature source was realized by using the vapor chamber heat spreader. The cost-effectiveness and simple manufacturing process were achieved by using the metal-etched wick structure. The temperature distribution was quantitatively investigated by using IR temperature imaging system at equivalent temperatures to the PCR thermal cycle. The standard deviation was measured to be within 0.7$^{\circ}C$ for each temperature cycle. This concludes that the presented isothermal temperature source enables no temperature gradient inside bio-sample fluid. Furthermore it can be applied to the cooling of the electronic devices due to its slimness and low thermal spreading resistance.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.12
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• pp.142-148
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• 1995

Sb ${\delta}$-doped Si layers were grown by Si MBE (Molecular Beam Epitaxy) system using substrate temperature modulation technique. The Si substrate temperatures were modulated between 350$^{\circ}C$ and 600$^{\circ}C$. The doping profile was as narrow as 41$\AA$ and the doping concentration of up to 3.5${\times}10^{20}cm^{3}$ was obtained. The film quality was as good as bulk material as verified by RHEED (Reflected High Energy Electron Diffraction), SRP (Spreading Resistance Profiling) and Hall measurement. Since the film quality is not degraded after the growth a Sb ${\delta}$-doped Si layer, the ${\delta}$-doped layers can be repeated as many times as we want. The doping technique is useful for many Si devices including small scale devices and those which utilize quantum mechanical effects.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.4
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• pp.263-270
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• 2020

In this study, the physical mechanism and diffusion effects in aluminium implanted silicon was investigated. For fabricating power semiconductor devices, an aluminum implantation can be used as an emitter and a long drift region in a power diode, transistor, and thyristor. Thermal treatment with O₂ gas exhibited to a remarkably deeper profile than inert gas with N₂ in the depth of junction structure. The redistribution of aluminum implanted through via thermal annealing exhibited oxidation-enhanced diffusion in comparison with inert gas atmosphere. To investigate doping distribution for implantation and diffusion experiments, spreading resistance and secondary ion mass spectrometer tools were used for the measurements. For the deep-junction structure of these experiments, aluminum implantation and diffusion exhibited a junction depth around 20 ㎛ for the fabrication of power silicon devices.

• Convergence Security Journal
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• v.21 no.1
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• pp.79-92
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• 2021

In a society where ICT technology is converged, the use of various network-connected devices such as IoT is spreading. Network-connected devices are inevitably exposed to the threat of hacking such as information leakage, and countermeasures need to be prepared to respond. Security certification system for IoT devices has been introduced to promote security of IoT products, and for this purpose, legalization and standardization of certification standards and methods are in progress. In line with this, in Korea, as the Information and Communication Network Act was revised in 2020, ICT convergence devices connected to the network were newly defined as "information and communication network connected devices," and the basis for the security certification system is being established. We summarized related domestic and foreign trends and suggest specific considerations for implementing the security certification system for IoT devices in South Korea.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.1B
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• pp.56-65
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• 2002

This paper proposes a novel transmit diversity technique, namely symbol split orthogonal transmit diversity (SS-OTD). In this technique, full path diversity and temporal diversity are achieved by combining orthogonal transmit diversity technique (OTD) technique with the symbol splitting method proposed by Meyer. Its performances is simulated for fundamental channels associated with the forward link of the IS-2000 system, and then compared with those of OTD and space-time spreading (STS). Our proposed method offers a 0.5-7.7dB performance improvement over OTD under various simulation environments and its performance is similar to STS. Moreover, compares with that of STS, the peak-to-average power ratio (PAR) of transmitted signals in SS-OTD is reduced by a maximal 1.35dB, which decreases the complexity of base station RF devices, such as power amplifiers. Thus, SS-OTD is comparable to STS in performance and superior to STS in the cost and efficiency of base station RF devices.