• 한국전자통신학회논문지
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• 제14권5호
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• pp.837-844
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• 2019

본 논문에서는 VANET(: Vehicular Ad Hoc Networks)환경에서 비-안전 애플리케이션을 위한 낮은 지연을 제공하기 위해 AMBM(: Adaptive Multi-channel Backoff Machisum)-MAC 프로토콜을 제안한다. 제안된 프로토콜은 우선 순위가 다른 비-안전 패킷간의 처리량의 극대화를 위해 WSA(: WAVE Service Advertisement)의 CW(: C hannel window)를 동적으로 조정하여 비-안전 패킷의 서비스품질을 보장한다. 또한 SC(: Service Channel)를 위한 채널조정 및 타임슬롯예약을 하기 위해 많은시간을 할당하고 CW 및 최적 CCI(: CC Interval)를 동적으로 조정함으로서 IEEE 1609.9, C-MAC(: Coordinated multi-channel MAC), Q-VCI(QoS Variable CCH Interval) 프로토콜보다 노드가 증가할 때 전송지연이 감소됨을 보인다.

• Journal of the Optical Society of Korea
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• 제19권3호
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• pp.284-296
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• 2015

It has been thought that males tend to use their brain hemispheres more laterally than females. However, recent fMRI studies have shown that there may be no difference in brain lateralization between genders. Functional near-infrared spectroscopy (fNIRS) presents a unique opportunity to acquire real time measurements of blood oxygenation changes to observe neural activity specific to the brain's left and right hemispheres. Using an in-house built multichannel fNIRS system, brain lateralization was observed from seven males and four females according to specially designed tasks for left and right hemisphere activation. The Pearson correlation coefficient and a modified Lateralization Index metric for continuous wave fNIRS systems were calculated to quantify brain lateralization. The preliminary results point to no significant difference in lateral hemodynamic changes between the genders. However, the correlation of symmetrical channel pairs decreased as the experiments progressed. To further develop this study, the subject's performance and the removal of global interference must be implemented for an improved study of brain lateralization.

• Biomedical Engineering Letters
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• 제8권4호
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• pp.373-382
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• 2018

Since epileptic seizure is unpredictable and paroxysmal, an automatic system for seizure detecting could be of great significance and assistance to patients and medical staff. In this paper, a novel method is proposed for multichannel patient-specific seizure detection applying the earth mover's distance (EMD) in scalp EEG. Firstly, the wavelet decomposition is executed to the original EEGs with five scales, the scale 3, 4 and 5 are selected and transformed into histograms and afterwards the distances between histograms in pairs are computed applying the earth mover's distance as effective features. Then, the EMD features are sent to the classifier based on the Bayesian linear discriminant analysis (BLDA) for classification, and an efficient postprocessing procedure is applied to improve the detection system precision, finally. To evaluate the performance of the proposed method, the CHB-MIT scalp EEG database with 958 h EEG recordings from 23 epileptic patients is used and a relatively satisfactory detection rate is achieved with the average sensitivity of 95.65% and false detection rate of 0.68/h. The good performance of this algorithm indicates the potential application for seizure monitoring in clinical practice.

• 대한후두음성언어의학회지
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• 제32권2호
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• pp.56-63
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• 2021

Laryngopharyngeal reflux disease (LPRD) is an inflammatory condition of the upper aerodigestive tract mucosa induced by reflux content from stomach. Some of vocal cord diseases are associated with laryngopharyngeal reflux. Because of the pathophysiological features, proton pump inhibitor shows therapeutic effect on some vocal cord diseases. As like that, the gastric reflux contents can make macroscopic or microscopic morphological changes in the upper aerodigestive tract mucosa. Although the pathophysiology of LPRD is relatively clear, clinical diagnosis is still difficult. The diagnosis of LPRD includes objective tests such as 24-hours multichannel intraluminal impedance-pH metry and subjective tests such as questionnaire method. However, the objective verification of reflux is difficult due to invasiveness of the method, and the questionnaire methods have limitations because many symptoms are not specific for LPRD. Moreover, most methods are not fully standardized until now. Despite these limitations, many researchers are struggling to standardize diagnosis and treatment of LPRD, and there are several new achievements recently. Therefore, the purpose of this article is to review the recent literature on the clinical presentation, diagnosis, and treatment of LPRD, and to systematize our knowledge.

• International Journal of Computer Science & Network Security
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• 제21권7호
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• pp.305-316
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• 2021

The objective is to recognize the better opportunities from targeted reveal advertising, to show a banner ad to the consumer of online who is most expected to obtain a preferred action like signing up for a newsletter or buying a product. Discovering the most excellent commercial impression, it means the chance to exhibit an advertisement to a consumer needs the capability to calculate the probability that the consumer who perceives the advertisement on the users browser will acquire an accomplishment, that is the consumer will convert. On the other hand, conversion possibility assessment is a demanding process since there is tremendous data growth across different information dimensions and the adaptation event occurs infrequently. Retailers and manufacturers extensively employ the retail services from internet as part of a multichannel distribution and promotion strategy. The rate at which web site visitors transfer to consumers is low for online retail, out coming in high customer acquisition expenses. Approximately 96 percent of web site users concluded exclusive of no shopper purchase[1].This category of conversion rate is collected from the advertising of social media sites and pages that dataset must be estimating and assessing with the concept of big data clustering, which is used to group the particular age group of people along with their behavior. This makes to identify the proper consumer of the production which leads to improve the profitability of the concern.

• 유통과학연구
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• 제20권8호
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• pp.69-79
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• 2022

Purpose: In the context of the emergence of industry 4.0, using mobile phones as a modern distribution channel to execute financial services is a significant solution for commercial banks' retail services and a gateway to promote financial inclusion and market development. Despite that service quality and customer satisfaction are two diverse notions and closely related to each other in the service sector, there is hardly a research which empirically examines the impacts of each dimensions of mobile banking service quality and customer satisfaction. Research design, data and methodology: This study first employs in-depth interview to explore various aspects of mobile banking service quality dimensions, including empathy, responsiveness, tangibility, assurance, and reliability that serves to develop measurement scales and hypothesis development. A quantitative survey is followed to collect data from 265 Vietnamese bank customers to empirically test the conceptual model. Resutls: Our findings indicate that more human-related factors including empathy, assurance, and responsiveness show the strongest impacts on customer satisfaction with mobile banking service while tangibility and reliability, as technical aspects, are less influential factors. Conclusions: Finally, some crucial implications are drawn for the banks to manage consumer behavior in mobile banking.

• 센서학회지
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• 제31권5호
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• pp.324-329
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• 2022

This paper proposes a shift-register-based multichannel ultrasonic focusing delay control method using a complex programmable logic device (CPLD) for a high resolution of ultrasonic focusing system. The proposed method can achieve the ultrasonic focusing through the delay control of driving signals of each ultrasonic transducer of an ultrasonic array. The delay of the driving signals of all ultrasonic channels can be controlled by setting the shift register in the CPLD. The experiment verified that the frequency of the clock used for the delay control increased, the error of the focusing point decreased, and the diameter of the focusing point decreased as the length of the shift register in the proposed method. The proposed method used only one CPLD for ultrasonic focusing and did not require to use complex hardware circuits. Therefore, the resources required for the design of an ultrasonic focusing system could be reduced. The proposed method can be applied to the fields of human computer interaction (HCI), virtual reality (VR) and augmented reality (AR).

• 품질경영학회지
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• 제50권2호
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• pp.221-233
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• 2022

Purpose: This study investigates how the salespersons behave in coordinating the multiple communication channels during supplier integration (SI) for new product development (NPD), especially when their engineers directly collaborate with the buyer. Methods: This study conducted a qualitative study to explore the dynamics of the supplier's salespersons during SI for NPD. With the support of a consumer goods manufacturer (focal firm) in South Korea, we interviewed several managers, including purchasing and engineering, from the focal firm and salespersons from eight tier-1 suppliers of the focal firm. Results: The results found that the supplier's salespersons show two different behaviors toward managing and controlling the collaboration between their engineers and the buyer: (1) Process regulating behaviors that control the flows of information or communication between the engineers and the buyer, and (2) knowledge regulating behaviors that directly and indirectly support the engineers to be equipped with accurate and complete knowledge so that they can share the right knowledge with the buyer. Conclusion: This study contributes to academia and practitioners as follows. To academia, this study fill the gap in the literature by introducing the distinct behaviors of the supplier's salesperson in SI for NPD. To practitioner, in addition, our findings present coordination mechanisms to manage and control multiple communications within an inter-organizational collaboration.

• ETRI Journal
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• 제46권2호
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• pp.323-332
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• 2024

Receiver and transmitter monolithic microwave integrated circuit (MMIC) multifunction chips (MFCs) for active phased-array antennas for Ka-band satellite communication (SATCOM) terminals have been designed and fabricated using a 0.15-㎛ GaAs pseudomorphic high-electron mobility transistor (pHEMT) process. The MFCs consist of four-channel radio frequency (RF) paths and a 4:1 combiner. Each channel provides several functions such as signal amplification, 6-bit phase shifting, and 5-bit attenuation with a 44-bit serial-to-parallel converter (SPC). RF pads are implemented on the bottom side of the chip to remove the parasitic inductance induced by wire bonding. The area of the fabricated chips is 5.2 mm × 4.2 mm. The receiver chip exhibits a gain of 18 dB and a noise figure of 2.0 dB over a frequency range from 17 GHz to 21 GHz with a low direct current (DC) power of 0.36 W. The transmitter chip provides a gain of 20 dB and a 1-dB gain compression point (P1dB) of 18.4 dBm over a frequency range from 28 GHz to 31 GHz with a low DC power of 0.85 W. The P1dB can be increased to 20.6 dBm at a higher bias of +4.5 V.

• Journal of Gastric Cancer
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• 제24권1호
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• pp.57-68
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• 2024

Reduced-port gastrectomy (RPG) includes all procedures derived from various efforts to minimize surgical invasiveness, with single-incision laparoscopic gastrectomy (SILG) being the ultimate reduced-port technique. However, there are challenges related to its feasibility, oncological validity, training, and education. This review describes the current issues and challenges, as well as the future prospects of RPG for gastric cancer. Gastrectomy, which started as an open surgery, has evolved into a laparoscopic surgery. With the advancements in laparoscopic technology, SILG has been used to minimize surgical scarring. However, owing to the technical difficulties of SILG, cases involving the addition of 1 trocar or needle grasper alongside the multichannel port have also been reported. Additionally, 3-port laparoscopic gastrectomy (3PLG) using only 3 trocars is also being performed. RPG, as a concept, includes a range of approaches such as SILG, 2-port laparoscopic gastrectomy, and 3PLG. These techniques aimed to reduce the number of ports or incisions required for laparoscopic gastrectomy. Despite technical difficulties, RPGs offer numerous advantages, including minimal invasiveness, excellent cosmetic outcomes, and the potential for improved postoperative recovery, such as reduced length of hospital stay and post-operative pain. It could be considered similar to conventional laparoscopic gastrectomy, and may not be oncologically inferior. Ongoing studies, such as the KLASS 12, are required to gain further insights.