• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.671-672
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• 2006

Recently Communication with using IrDA is bing used in various fields. In this paper I designed a receiver by fabricating hardware that used to be fabricated through software, so anyone who don't have knowledge on IrDA can receive Ir Signal easily. This receiver can communicate with CPU through 8 bit data and 3 bit address. Also this receiver can use user-needed CLK because this receiver embodied 16 bit CLK Prescaler.

• Journal of Communications and Networks
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• v.8 no.3
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• pp.275-285
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• 2006

Suitable for multi-input multi-output (MIMO) communications, the joint beamforming space-time block coding (JBSTBC) scheme is proposed for high-speed downlink transmission. The major functionality of the scheme entails space-time block encoder and joint transmit and receive eigen-beamformer (EBF) incorporating with block-ordered layered decoder (BOLD), and its operating principle is described in this paper. Within these functionalities, the joint EBFs will be utilized for decorrelating fading channels to cause an enhancement in the spatial diversity gain. Furthermore, to fortify the capability of layered successive interference cancellation (LSIC) in block-ordered layered decoding process, this paper will develop a simple ad-hoc transmit power discrimination scheme (TPDS) based on a particular power discrimination function (PDF). To confirm the superior behavior of the proposed JBSTBC scheme employing ad-hoc TPDS, computer simulations will be conducted under various channel conditions with the provision of detailed mathematical derivations for clarifying its functionality.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05a
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• pp.32-35
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• 2004

In this paper, we propose two novel high-rate high-performance space-time codes for multiple-input multiple-output (MIMO) systems. When $n_{T}$ transmit antennas and $n_{R}$ = $n_{T}$ receive antennas are deployed, the two proposed codes respectively offer transmission rates of ( $n_{T}$ -I) and ( $n_{T}$ - 2) symbols per channel use and diversity orders of 3 and 5. As a consequence, our proposed codes allow the MIMO systems to employ a simple detection technique based on QR decomposition. Moreover, for equal or even higher spectral efficiencies, our proposed codes always provide much better bit error rate (BER) performances than V-BLAST architecture does when $n_{R}$ = $n_{T}$. Computer simulation is given to verify performances of our proposed codes.sed codes.des.

• ETRI Journal
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• v.44 no.1
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• pp.117-124
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• 2022

In this paper, the performance of precoding-aided differential spatial modulation (PDSM) systems with optimal transmit antenna subset (TAS) selection is examined analytically. The average bit error rate (ABER) performance of the optimal TAS selection-based PDSM systems using a zero-forcing (ZF) precoder is evaluated using theoretical upper bound and Monte Carlo simulations. Simulation results validate the analysis and demonstrate a performance penalty < 2.6 dB compared with precoding-aided spatial modulation (PSM) with optimal TAS selection. The performance analysis reveals a transmit diversity gain of (N_T-N_R+1) for the ZF-based PDSM (ZF-PDSM) systems that employ TAS selection with N_T transmit antennas, N_S selected transmit antennas, and N_R receive antennas. It is also shown that reducing the number of activated transmit antennas via optimal TAS selection in the ZF-PDSM systems degrades ABER performance. In addition, the impacts of channel estimation errors on the performance of the ZF-PDSM system with TAS selection are evaluated, and the performance of this system is compared with that of ZF-based PSM with TAS selection.

• Journal of the Korean Dietetic Association
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• v.18 no.1
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• pp.1-15
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• 2012

The purpose of this study was to provide fundamental data for health promotion and improvement of the dietary life in students who receive school lunch support (SLS) by comparative analysis of food service satisfaction, dietary habits, and nutrition intakes according to SLS. The subjects of this study consisted of 258 boys and 233 girls at a middle school in Incheon. The students' average age was 14.9 years, average height was 161.3 cm, and average weight was 52.0 kg. The breakfast eating frequency of the No-SLS (NSLS) group was significantly greater than that of the SLS group (P<0.05). The time spent for eating breakfast in the SLS group was significantly shorter than that of the NSLS group for boys. There was no significant difference in dietary attitudes according to SLS. For satisfaction of the quantity and diversity of the school lunch menu in girls, the SLS group had higher satisfaction than the NSLS group. The daily energy intake of the SLS group was significantly lower than that of the NSLS group in both boys and girls. The majority of daily nutrients intakes in the SLS group were also significantly lower than those in the NSLS group. In summary, the female students in the SLS group were more satisfied with school lunch service than general students. However, SLS students less frequently ate breakfast and showed lower energy and nutrient intakes. Therefore, in order to improve the nutritional status and dietary life of students who receive school lunch support, consistent nutrition management and support in schools are required.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.2A
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• pp.202-213
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• 2004

In this paper, we propose a preamble structure and synchronization/channel estimation methods for OFDM-based multiple antenna WLAN systems that have 200Mbps transmit rate. With the proposed preamble structure, multiple antenna WLAN systems are backward-compatible with IEEE 802.11a systems which use the same 5㎓ band and synchronization performance is better than that of single antenna OFDM systems. For channel estimation, the preamble overhead is small and performance degradation by timing synchronization error that causes the critical problem of conventional comb-type multiple antenna channel estimation method also can be minimized by frequency domain phase recovery. Synchronizer and channel estimator for proposed preamble structure are implemented and verified using Verilog HDL. For the system with 4 transmit antennas and 4 receive antennas, about 150K gates are needed for synchronizer and 12K gates for channel estimator.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12A
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• pp.1147-1155
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• 2008

In this paper, we derive the probability density function (PDF) of end-to-end signal-to-noise ratio (SNR) for t he dual-hop MIMO (Multiple-Input Multiple-Output) DCF (Decouple-and-Forward) system. We also provide the end-to-end bit error ratio (BER) with M-ary PSK constellations for four antenna combinations. These are (1,8,1), (8,1,8), (2,4,2), and (4,2,4). Each number in the parentheses is the number of the transmit antenna at the source, the transmit and receive antenna at the relay and the receive antenna at the destination, respectively. We show t hat the end-to-end BER expression with M-ary PSK constellations makes an exact match with numerical results. We also show that MIMO DCF relay system achieves spatial diversity.

• Journal of Broadcast Engineering
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• v.15 no.6
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• pp.749-756
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• 2010

The signal space diversity is one of the promising transmission techniques in next generation mobile TV service. However, DVB-T2 does not consider the multiple antennas (MIMO) so that the cyclic Q-delay method, a component interleaver in DVB-T2, causes a critical issue in detecting symbols at the receiver side by increasing the inter-symbol dependency. To solve this problem, the component-swapping technique is proposed, which limits the inter-symbol dependency in order to reduce detection complexity. In this paper, the achievable gain of a component-swapping technique combined with 16K LDPC code defined in DVB-T2 is evaluated by computer simulations. From the results, the gain is confirmed in terms of BER and receive complexity compared to legacy component interleaver methods.

• Journal of Practical Engineering Education
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• v.11 no.2
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• pp.305-311
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• 2019

Many universities offer mileage system as part of their student reward program. The mileage system provides mileage to students who participated in on-campus extracurricular programs, and awards scholarships regardless of grades based on the mileage earned. The purpose of this study is to identify the effect of students' perception of college mileage system on loyalty and to compare the difference in loyalty between those who received mileage and those who did not. To this end, the effect of loyalty was studied empirically by classifying the perception of college mileage into five categories: the cash value, aspirational value, diversity of benefits, convenience, and relevance. The results showed that aspirational value, diversity of benefits and relevance had a positive effect on loyalty, while cash value and convenience did not. In addition, the effect of cash value on loyalty was higher in those who received mileage than those who did not. In terms of relevance, higher loyalty was found in group that did not receive mileage than those who did.

• The Journal of Korean Physical Therapy
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• v.20 no.4
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• pp.61-69
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• 2008

Purpose: We evaluated caregivers' understanding of patients' diseases and disuse syndrome, the understanding of exercise and massage related to rehabilitation and the necessity of education about these, the difference in education and realities of the care-giving field, and the extra services needed in the field. Methods: The survey using questionnaires was performed from June 2008 to August 2008 with 220 people participated in caregive education programme in daegu city and area near dagu city. Among the 220 submitted questionnaires, 184 which were faithfully answered were selected and they were analyzed by i-STATistics statistical program. Results: The educational focus of the first and second level caregivers, as defined by the second clause of the 29th article of the Elderly Welfare law, is on basic knowledge of diseases such as dementia, stroke, and depression. However, other diseases are not covered and the information does not include information on decreased function, complications, functional rehabilitating exercises, or preventing disuse syndrome for long term patients. The most common diseases, in order of prevalence, are stroke, dementia, diabetes mellitus, Parkinson disease, arthritis, and geriatric inertness. The general level of awareness about disuse syndrome was low, and patients, while understanding the need for massage and rehabilitative exercise, receive little education about the proper methods and therefore cannot use them. Patients also did not understand how participating in these activities could reduce medical fees, indicating that further education on massage and rehabilitative exercise is needed. Caregivers desired to include positive rehabilitation, massage, and exercise-related services in their services. Finally, differences in caregiver education and reality resulted from a lack of diversity in education. Conclusion: We suggest providing education on disuse atrophy and improving the lack of diversity in the care-giving education system.