• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.5201-5206
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• 2014

A 'Light switch remote control' was made with an android smartphone and a smart light switch, which can use wireless communication on this paper. A smart light switch uses an embedded board and Bluetooth communication to receive and transmit data, and it receives and sends data again with a smartphone and wireless communication. This study used the flexibility of sensors that could be added later to utilize the embedded board as a gateway. This skill is being serviced now in a new apartment and building. On the other hand, existing households that do not support this skill can use it if they change only the switch. In conclusion, this system ensured user convenience and flexibility of system.

• Journal of the Korea Society of Computer and Information
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• v.13 no.6
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• pp.211-216
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• 2008

Gap fillar antennas are needed for serving the high quality of DMB through the cellular phone by eliminating the shadow regions among buildings or underground. We implement Quadrifilar Helical Antenna using phase difference with PCB feeding lines without coaxial cables and four impedance matching circuits. It is shown that the antenna characteristics is affected by the size and diameter through the simulation process using MicroWave Studio and it is applied for implementing QHA. Experiment results confirm that the performance can be gained as same as the simulation data by using the phase difference with PCB feeding lines without additional impedance matching circuits.

• Journal of the Korea Society of Computer and Information
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• v.11 no.2 s.40
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• pp.201-211
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• 2006

The standardization of third Generation Partnership Project(3GPP) has been performed in of order to support interactive multimedia services under mobile environments. In this 3GPP, transmit diversity solutions are applied to increase the available diversity effectively using 2 or more antennas. In this paper, we analyzer the performances on STTD(Space Time Transmit Diversity) technique and its modified techniques such as STTD-OTD, CL-STTD, and 4TX-STTD out of open loop transmit diversities that the standardization of 3GPP has released. We also propose the open loop transmitter and receiver diversities to add the receiver diversity. We analyze and discuss the performance of the proposed techniques and using the Matlab simulation under the flat fading channel environment.

• Journal of KIISE:Information Networking
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• v.28 no.3
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• pp.417-425
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• 2001

Since First-Come-First-Served discipline makes it difficult to satisfy the diverse quality of scrvicc(QoS) requirements for each c-oonection, traffic isolation has been proposed for guaranteeing the desired QoS through explicit bandwidth allocation to each virtual connection(VC) in A TM networks. For this purpose, we propose a rate-controlled cell multiplexer using a simple "periodic token-based regulator" per- Vc. The proposed multiplexer realizes VC isolation, while still operating work'||'&'||'not;conservingly. We first discuss its major properties, and then examine its features with respect to the characteristics of the output traffic streams and the traffic isolation of individual VC's, by simulation.n.

• Management & Information Systems Review
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• v.32 no.3
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• pp.173-188
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• 2013

I guess that e-learning buying behaviors have some selection criteria which are interactivity, contents quality, perceived usefulness, and corporate reputation. And I propose that the effects of selection criteria on adaptation intention are moderated by buyer-user status. To accomplish research purpose, I conducted a field survey with a self-administered questionnaire in both user-buyer and analysed the causal relations among the variables by regression analysis. Findings are these. In all of the customer, interactivity, perceived usefulness, and corporate reputation had positive effects on re-attending intention to another e-learning class. In case of users(students), interactivity, contents quality, and perceived usefulness had positive effects, but buyer(parents) showed both perceived usefulness and corporate reputation had positive effects on re-attending intention.

• The Journal of Society for e-Business Studies
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• v.16 no.3
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• pp.225-247
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• 2011

Universities have been investing in their information systems to keep their management functions working efficiently and effectively. Thanks to these efforts, faculty members and other university employees can perform their tasks efficiently almost anywhere and anytime. Several universities embarked upon information systems projects to take advantage of emerging information technologies in their administration and management. Only a limited number of universities have achieved their objectives; some others have been even tinkering with the idea of abandoning their newly developed academic information systems. The development of academic information systems often start with a relatively high risk of system failure. Sometimes, these systems encounter unforeseen obstacles or fail in systems development. These universities with problems also can overcome these issues by collecting their wisdom. The mindfulness theory is suitable for dealing with implementing academic information systems. This research analyzes an academic information systems development case from a mindfulness perspective, and also addresses its research implications and theoretical contributions.

• The KIPS Transactions:PartC
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• v.11C no.5
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• pp.671-676
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• 2004

In this paper, we propose ultra-fast multimedia optical subscriber access network using optical frequency domain CDMA method in order to access the multimedia with multiple data rates. We numerically analyze the effects of spectral power distortion in the light source for the optical CDMA system modified PN codes and FBG(Fiber Bragg Grating)s. In the proposed multiple-rate multimedia access optical networks, the performances such as BER(Bit Error Rate) are the same for all data regardless of data rates in the case of the same number of simultaneous ONU. In the proposed ultra-fast multimedia optical subscriber access network, the performances for all data are much more improved than those in the conventional system.

• Information Systems Review
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• v.11 no.2
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• pp.1-22
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• 2009

IT advances rapidly and is widely used both in for-profit and non-profit organizations. Academic institutions are no exception in the adoption of new IT such as e-libraries, e-blackboards, as well as Web 2.0 services. However, administrative information systems in colleges and universities often lag relatively behind. One of the reasons of this is that academic institutions tend to focus only on the implementation of IT, while neglecting the mindfulness needed for post-implementation. This study develops a new perspective for the sustainability of academic information systems through the lens of mindfulness. The results from administrating a nation-wide survey of universities and colleges provide the variations of a ranking of the critical success factors between implementation and post-implementation. The findings imply that both individual and collective mindfulness are needed to implement and, especially, sustain administrative IS successfully in academic institutions.

• Journal of the Korea Society of Computer and Information
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• v.16 no.12
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• pp.175-185
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• 2011

The threshold level of a receiver is analyzed for the simplification of system and the improvement of upstream data ratios in optical subscriber network of which the upstream date rate and the optical transmitted power are changed to meet the requested BER (Bit Error Rate) defined per interactive multimedia services. In asynchronous optical subscriber network of which the upstream to downstream data ratios are 1:1/2, 1:1/4, 1:1/8 and 1:1/16 with manchester coded downstream and NRZ (Non Return to Zero) downstream re-modulation, the BER performance is theoretically analyzed and it is performed by simulation with MATLAB according to the four types of downstream data for four models. The results have shown that in the cases which the upstream to downstream data ratios are 1:1/4, 1:1/8 and 1:1/16 the conventional receiver with threshold level of 1/2 can be applied regardless of average received optical powers and the BER is not much deteriorated compared with using the optimal threshold level. In the case that the upstream to downstream data ratio is 1:1/2 the threshold level in an optical receiver could be fixed at 1/3 and the BER is not much deteriorated compared with using the optimal threshold level as the average received optical power increases.