• Asia pacific journal of information systems
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• v.15 no.2
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• pp.65-96
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• 2005

It is generally believed that, compared to traditional commerce, Electronic Commerce(EC) is more difficult to gain and sustain customers. One of the major reasons that customers do not use EC is lack of trust. Previous researches on the EC user's trust suggested that risk is an antecedent of trust and the concept of trust is highly related to risk. This study proposed a combined model in which includes the factors based on generic information security risk analysis methodology and trust factors in EC. The objectives of this study are follows; first, investigating the relationship between trust and risk that are antecedent factors of purchase intention, and second, examining the validity of information security risk analysis approach in EC environment. Based on the survey results of 143 MBA students statistical analysis showed that factors like threats and controls were significantly related to risk, but assets did not have statistically significant relationship with risk. Controls and knowledge of EC had meaningful effect on user's trust. This study found that risk analysis methodology which is generally used at organizational level is practically useful at user level on EC environment. In conclusion, the results of this study would be applied to generic situation of information security for analyzing and managing the risk. Besides, this study emphasized that EC vendors need to pay more attention to the information security risk to gain customer's trust.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.11
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• pp.1209-1216
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• 2009

This paper presents an efficient Quantized Equal Gain Transmission(QEGT) codebook index searching technique for MISO beamforming system in a Rayleigh flat fading channel. The searching time for the optimum weight vector among the codebook vectors increases exponentially when the codebook size increases linearly, although the bit error rate decreases. So, newly defined simple metric is proposed for fast searching, which determines a few candidates. Then the conventional method combined with accurate search algorithm selects the optimal index. This strategy significantly reduces the overall search time, while maintaining almost the same bit error rate performance. Furthermore, as the codebook size increases, the search time is considerably decreased compared to that of the conventional approach.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2000.11a
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• pp.63-65
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• 2000

Two experiments were conducted to investigate the effects of feeding single or combined probiotics on performance and intestinal microflora of broiler chicks for five weeks. Diets based on corn and soybean meal contained 21.50, 19.0% CP and 3,100, 3,150 kcal/kg ME for starting and finishing period, respectively. Lactobacillus salvarius isolated from chicks intestine(LSC), Lactobacillus salvarius isolated from piglet(LSP) Bacillus polyfermenticus(BP) were fed with alone and mixed ones at the level of 0.21 and 0.1% in experiment 1 and 2. Three hundred eighty four chicks were randomly assigned to eight treatment with four replicates of 12 chicks each per treatment. Weight gain, feed consumption, feed conversion ratio(FCR) were weekly measured for 5 weeks. The number of intestinal microflora was examined at the end of experiment. There were no significant different weight gain of all treatment in both experiments. Feed consumption were not shown consistency. Chicks fed LSC alone showed the lowest feed conversion ratio of all treatment in experiment 1, but was not consistency in experiment 2. The number of Lactobacillus spp. tended to increase in chicks ileum fed probiotics treatments, whereas it was not consistency in cecum. The number of ileal E. coli was not decreased in BP treatment.

• Journal of Korea Society of Industrial Information Systems
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• v.16 no.4
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• pp.19-26
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• 2011

Relay-assisted multiple input multiple output (MIMO) technique has become a promising candidate for next generation broadband wireless communications. In this paper, we propose maximum ratio combining (MRC) minimum mean-square-error (MMSE) equalization for single carrier-frequency domain equalizer (SC-FDE) in amplify-and-forward (AF) relaying networks. The performance of SC-FDE system can be improved considerably by achieving both the diversity gain and the MMSE equalization gain when the signals from source-destination (S->D) and source-relay-destination (S->R->D) are combined and equalized by means of the MMSE criteria. We find the weighting coefficients of MRC combining and the tap coefficients of MMSE equalizer for SC-FDE in AF relaying networks. Simulation results show that the proposed relay-based system considerably outperforms the conventional SC-FDE system.

• Journal of electromagnetic engineering and science
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• v.9 no.1
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• pp.7-11
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• 2009

An Ultra-WideBand(UWB) Low-Noise Amplifier(LNA) is proposed and is implemented in a $0.18-{\mu}m$ CMOS technology. The proposed UWB LNA provides excellent wideband characteristics by combining a High-Pass Filter (HPF) with a conventional resistive-loaded LNA topology. In the proposed UWB LNA, the bell-shaped gain curve of the overall amplifier is much less dependent on the frequency response of the HPF embedded in the input stage. In addition, the adoption of fewer on-chip inductors in the input matching network permits a lower noise figure and a smaller chip area. Measurement results show a power gain of + 10 dB and an input return loss of more than - 9 dB over 2.7 to 6.2 GHz, a noise figure of 3.1 dB at 3.6 GHz and 7.8 dB at 6.2 GHz, an input PldB of - 12 dBm, and an IIP3 of - 0.2 dBm, while dissipating only 4.6 mA from a 1.8-V supply.

• YAKHAK HOEJI
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• v.45 no.5
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• pp.545-556
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• 2001

Crude saponin fractions were isolated using non-ionic resin chromatography from Ginseng Radix Alba (PG) and Gynostemmae Herba+ (GP). These saponin fractions were orally administered to strep- tozotocin (STZ)-induced diabetic rats for 2 weeks and to high-fat diet-induced obese rats for 4 weeks. Treatment with either PG saponin or GP saponin at a dose of 1 mg/kg significantly decreased the plasma glucose level to that of glibenclamide treated or normal groups. The increased plasma triglyceride (TG) level in diabetic rats was decreased by 50% with PG or GP saponin treatment. Combined administration of PG and GP saponins with different ratios (total dose of 1 mg/kg) also had the similar effects on the blood glucose and TG levels with that of PG or GP alone. Treatments with GP (1 mg/kg) or GP (0.5 mg/kg) and PG (0.5 mg/kg) together significantly suppressed the rise in TG levels induced by high-fat diet whereas slightly suppressed the rise in the total cholesterol level. The body weight gain was also decreased both in the two saponin treated groups. These results demonstrate that either alone or mixture of PG and GP have similar degree of effects on hyperglycemia and hyperlipidemia.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2123-2125
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• 2001

In thermal power plant, the efficiency of a combined power plant with a gas turbine increases, exceeding 50%, while the efficiency of traditional steam turbine plants is approximately 35% to 40%. Up to the present time, the PID controller has been used to operate this system. However, it is very difficult to achieve an optimal PID gain without any experience, since the gain of the PID controller has to be manually tuned by trial and error procedures. This paper focuses on the neural network tuning of the 2-DOF PID controller with a separated 2-DOF parameter (NN-Tuning 2-DOF PID controller), for optimal control of the Gun-san gas turbine generating plant in Seoul. Korea. In order to attain optimal control, transfer function and operating data from start-up, running, and stop procedures of the Gun-san gas turbine have been acquired, and a designed controller has been applied to this system. The results of the NN-Tuning 2-DOF PID are compared with the PID controller and the conventional 2-DOF PID controller tuned by the Ziegler-Nichols method through experimentation. The experimental results of the NN-Tuning 2-DOF PID controller represent a more satisfactory response than those of the previously-mentioned two controller.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.8
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• pp.1407-1413
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• 2000

This paper presents a feedforward linear power amplifier (LPA) using error feedback technique to achieve low intermodulation distortions(IMD) of power amplifiers for base stations. Especially, the proposed linear power amplifier is applied to feedforward technique combined with error feedback technique, which has no loss of amplifier gain unlike typical feedback technique. The proposed LPA is designed by using HP ADS ver. 1.3, fabricated. When two-tone signals at 1850 MHz and 1851.25 MHz with -7 dBm/tone from synthesizers are injected into the main power amplifier with gain of 28 dB and P1dB of 1W, the proposed LPA could reduce more than 35 dB.

• Safety and Health at Work
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• v.12 no.3
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• pp.365-369
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• 2021

Background: Law enforcement communications (i.e., 911 dispatch and call takers) is a challenging and stressful occupation. The purpose of this study is to identify the main stressors associated with employment in law enforcement communications, and to identify and provide context to how these stressors affect workers' health and wellbeing. Methods: This research study included focus groups with 23 call takers and 911 dispatchers employed by a large, urban law enforcement agency in 2018. Thematic analyses were conducted to identify trends. Results: Four themes of stressors emerged (i.e., the high stakes nature of some 911 calls for service, understaffing, supervisor-related stress, and recruiting practice). Two health-related themes emerged as being occupation-related: weight gain and poor sleep patterns/insufficient sleep). Specifically, participants reported negative eating habits resulting in weight gain and obesity, lack of sleep and irregular sleep schedules, and development of hypertension and/or diabetes since beginning their jobs. Conclusion: Law enforcement communications professionals experience a number of the same stressors facing law enforcement officers in patrol. These stressors, combined with the sedentary nature of the job, could result in long-term, chronic health problems.

• Journal of Internet Computing and Services
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• v.8 no.4
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• pp.61-70
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• 2007

In this paper, we propose and observe the Adaptive Modulation system with optimal Turbo Coded V-BLAST(Vertical-Bell-lab Layered Space-Time) technique that is applied the extrinsic information from MAP Decoder in decoding Algorithm of V-BLAST: ordering and slicing. And comparing the proposed system with the Adaptive Modulation system using conventional Turbo Coded V-BLAST technique that is simply combined V-BLAST with Turbo Coding scheme, we observe how much throughput performance and SNR has been improved. In addition, we show that the proposed system using STD(Selection Transmit Diversity) scheme results in on improved result, By using simulation and comparing to conventional Turbo Coded V-BLAST technique with the Adaptive Modulation systems, the optimal Turbo Coded V-BLAST technique with the Adaptive Modulation systems has SNR gain over all SNR range and better throughput gain that is about 350Kbps in 11dB SNR range. Also, comparing with the conventional Turbo Coded V-BLAST technique using 2 transmit and 2 receive antennas, the proposed system with STD scheme show that the improvement of maximum throughput is about 1.77Mbps in the same SNR range and the SNR gain is about 5.88dB to satisfy 4Mbps throughput performance.