• Proceedings of the Korean Operations and Management Science Society Conference
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• 2008.10a
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• pp.464-486
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• 2008

Purpose. Electronic intermediaries (e-intermediaries) are gaining significance in international marketing with the rapid development of e-commerce. The goal of this study is to explain empirically what leads to a higher use of this relatively new exportation alternative. Relying on a resource-based view as our research foundation, we focus on information technology (IT) and non-IT factors as possible determinants. Further, this study brings arguments offered by transaction cost theorists to explain the other non-IT determinants. Methodology/Approach. Data are collected from small and medium-sized enterprises (SMEs) in the electronic industry in Korea and the U.S to ensure generalizability. Ordinary least square (OLS) regression is utilized to analyze the data. Findings. This study raises new issues regarding a relatively new type of exporting channel, e-intermediary. Exporting is regarded as the most appropriate strategy for SMEs in international commerce. A number of SMEs stay away from exporting due to limited resources or lack of knowledge regarding foreign markets. The findings in this study should help SMEs use e-intermediaries more widely by developing appropriate IT-related resources (IT-related human and relationship assets) and dealing with non-IT factors (international competence, environmental uncertainty, and duration of relationship) effectively. Originality/Value/Contribution. This study illustrates the significant role of e-intermediaries, which may help SMEs to penetrate the global market effectively. Finding relevant sources in the global e-marketplace is a challenge for non-experienced users like SMEs. This study proposes e-intermediaries as an effective alternative for them. Another contribution of this study is to show how the use of indirect exporting channels, e-intermediaries, decrease costs in exporting transactions. This study suggests an e-intermediary as a hybrid exporting channel to balance risk and profit.

• Knowledge Management Research
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• v.23 no.3
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• pp.285-311
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• 2022

In this study, based on the S-O-R framework, how individual's stimuli (i.e., video characteristics, YouTuber characteristics, real-time broadcasting characteristics of YouTube channel) form organisms (i.e., perceived usefulness, perceived pleasure, social presence), leading to viewers' responses (i.e., continuous watching intention, paid sponsorship intention) on real-time YouTube channels. For this purpose, a research model and hypotheses were constructed, and 369 questionnaire data collected from users of real-time broadcasting channel services on the YouTube platform were analyzed. Result findings confirmed that some video/YouTuber/real-time broadcasting characteristics significantly affect viewers' perceived usefulness/perceived pleasure/social presence, and further influence continuous watching/paid sponsorship intentions. Theoretical and practical implications of the findings are discussed in conclusion.

• The Journal of the Acoustical Society of Korea
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• v.23 no.2E
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• pp.56-67
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• 2004

Despite abundant research outcomes of blind source separation (BSS) in many types of simulated environments, their performances are still not satisfactory to be applied to the real environments. The major obstacle may seem the finite filter length of the assumed mixing model and the nonlinear sensor noises. This paper presents a two-step speech enhancement method with multiple microphone inputs. The first step performs a frequency-domain BSS algorithm to produce multiple outputs without any prior knowledge of the mixed source signals. The second step further removes the remaining cross-channel interference by a spectral cancellation approach using a probabilistic source absence/presence detection technique. The desired primary source is detected every frame of the signal, and the secondary source is estimated in the power spectral domain using the other BSS output as a reference interfering source. Then the estimated secondary source is subtracted to reduce the cross-channel interference. Our experimental results show good separation enhancement performances on the real recordings of speech and music signals compared to the conventional BSS methods.

• Journal of electromagnetic engineering and science
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• v.10 no.3
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• pp.138-145
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• 2010

In this paper, we report the test results of a small-scale prototype that implements an analogue-beam-formed phased antenna array in the E-band. A four-channel dual-conversion receive RF module for 71~76 GHz frequency band has been developed and integrated with a linear end-fire antenna array. Measured performance is very close to the simulated results. An ad-hoc wireless communication system has also been demonstrated. Low BER was measured for an 8PSK data stream at 1.5 Gbps with the receive array beam formed in the direction of arrival of the transmitted signal. To our knowledge this is the first steerable antenna array reported to date in the E-band.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.11
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• pp.1424-1431
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• 2004

With traditional experimental methods such as the secondary fluid (e.g., water) calorimetric method, it is very difficult to accurately test the local condensation heat transfer inside mini-channels. Hence, there are large discrepancies between the results of previous studies. The experimental methods as well as unidentified sources of uncertainties could be reasons for such discrepancies. In this study, innovative experimental techniques were developed to measure the in-tube condensation heat transfer coefficient. With these techniques, very low heat dissipation rates such as several watts from the mini-channel could be estimated and low mass flow rates below the 0.1 ㎏/h could be measured with reasonable uncertainties. To the authors' knowledge, these techniques provide a unique experimental apparatus for measuring the condensation heat transfer coefficients inside the sub-millimeter hydraulic diameter single channels.

• Journal of Distribution Science
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• v.18 no.3
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• pp.67-76
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• 2020

Purpose: Consumers are affected by the purchase of a large number of opinions or support during the online purchasing process. This can be defined as the term of 'social decisions' on line. This paper seeks to explore the factors of influence on social decisions in on-line environment and to study in depth. Methodology: The purpose of this paper is to empirically examine the impact of factors on online social decisions. To verify the hypothesis of study, This study collected 256 from Seoul City, Gyeonggi Province and Chungcheong Province through Survey. Results: According to the research results, First, eWOM information usefulness have a positive impact on online social decisions, Second, online network connectedness have a positive impact on online social decisions. Third, innovative product have a positive impact on online social decisions. and the lower the category of knowledge, the more inclined it is to make online social decisions. Finally, social decisions have a positive impact on purchasing decisions about product. It is most significant that academic research has advanced consumer behavior in response to recent changes in the consumption environment. It is meaningful that we have studied in depth the changing consumer decision process in online channel environment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.8A
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• pp.745-751
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• 2006

The transmitter requires knowledge of the channel status information in order to adopt the adaptive modulation and coding scheme(AMC) for OFDM system. But in the outdoor environment which the users have high mobility, the channel status information from the users is outdated, so that it induces the degradation of system throughput and packet error rate(PER) performance. To solve this problem, researches about applying channel prediction technique to the AMC scheme have been proceeded. Most channel prediction techniques assume that there is no channel variation in the predefined time duration, e.g., a slot. As a result, those techniques cannot compensate the degradation of PER performance resulting from the rapid variation of channel during the slot duration. This paper introduces a novel channel prediction technique for OFDM/FDD system to support adaptive modulation and coding scheme over rapidly time-varying multipath fading channel. The proposed channel prediction technique considers the time-varying nature of channel during the slot duration. Simulation results show that the AMC scheme of OFDM/FDD system utilizing the proposed channel prediction technique can guarantee the target PER of 1% without any loss of system throughput compared with the case supported by the conventional channel prediction under ITU-R Veh A 30km/h.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.5
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• pp.755-764
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• 2001

In this paper, we propose maximum likelihood (ML) decision feedback channel estimation (DFCE) for M-ary orthogonal modulation in direct sequence/code division multiple access (DS/CDMA) systems. The proposed DFCE uses the maximum combiner output in a RAKE receiver as decision feedback information, enabling M-ary orthogonal signals to be demodulated coherently and a RAKE receiver to use a em maximal ration combining (MRC) scheme. However, the performance of the proposed DFCE in the multiuser environment is severely degraded due to multiple access interference (MAI). To overcome this problem, a multistage parallel interference cancellation (PIC) scheme is combined with the proposed DFCE for multiuser environments. Accurate knowledge of the channel coefficient estimated by the proposed DFCE is used to regenerate the signal of each user for the multistage PIC scheme. According to the results of our simulations, the performance of coherent demodulation using the proposed system is significantly improved in comparison with conventional noncoherent demodulation.

• Journal of Communications and Networks
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• v.18 no.3
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• pp.351-363
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• 2016

This paper investigates the performance of interference-limited two-way transmission protocols in the Rayleigh fading channels. New lower bound of outage probability and approximate expression of bit error rate (BER) for three-phase two-way relaying (3P-TWR) protocol are derived in closed-form. These expressions are valid for arbitrary signal-to-noise ratio values, numbers of co-channel interferers and amajority of modulation formats employed in the practical system. Then a comparative study is developed for the performance of three two-way transmission protocols, i.e., direct transmission (DT) protocol, two-phase two-way relaying (2P-TWR) protocol and 3P-TWR protocol based on the asymptotic expressions of outage probability and BER. On the basis of the theoretical results, the thresholds on the strength (variance) of direct channel and target rate for the relative performance of different protocols are obtained and the effect of interferences at the terminal and relay on the relative performance is analyzed. The results present key insights on how to choose proper two-way transmission protocol with the knowledge of fading channels, required date rate and modulation format to optimize the system performance in the practical interference-limited scenarios. Simulation results are presented to validate the theoretical analysis.

• Journal of Korea Society of Industrial Information Systems
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• v.20 no.3
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• pp.61-69
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• 2015

This study presents a probabilistic knowledge discovery method to interpret heart rate variability (HRV) based on time and frequency domain indexes, extracted using discrete wavelet transform. The knowledge induction algorithm was composed of two phases: rule generation and rule estimation. Firstly, a rule generation converts numerical attributes to intervals using ROC curve analysis and constructs a reduced ruleset by comparing consistency degree between attribute-value pairs with different decision values. Then, we estimated three measures such as rule support, confidence, and coverage to a probabilistic interpretation for each rule. To show the effectiveness of proposed model, we evaluated the statistical discriminant power of five rules (3 for atrial fibrillation, 1 for normal sinus rhythm, and 1 for both atrial fibrillation and normal sinus rhythm) generated using a data (n=58) collected from 1 channel wireless holter electrocardiogram (ECG), i.e., HeartCall$^{(R)}$, U-Heart Inc. The experimental result showed the performance of approximately 0.93 (93%) in terms of accuracy, sensitivity, specificity, and AUC measures, respectively.