• 한국정보통신설비학회:학술대회논문집
• /
• 2004.08a
• /
• pp.46-49
• /
• 2004

레이저 다이오드 (LD)의 광 직접 변조시 광자와 전자의 동역학에 의하여 입출력 관계가 결정된다. 이는 LD의 직접 변조 시 대역폭을 제한하는 요소로 작용한다. 높은 대역폭을 가지는 광송신기 설계를 위하여 LD의 등가회로 분석은 필수적이다. LD의 등가회로는 E/O response를 이용하여 소신호 분석을 통해 얻을 수 있으며, E/O response는 rate equation을 이용하여, 구할 수 있다. LD의 등가회로는 직렬 저항값, 기생 커패시턴스, 외부 회로와의 연결을 위한 와이어에 기인하는 인덕턴스 성분 등으로 구성된다. 본 논문에서는, rate equation을 사용하여 계산된 결과를 이용하여, LD의 등가회로를 도출하였다.

• Nuclear Engineering and Technology
• /
• v.53 no.5
• /
• pp.1483-1490
• /
• 2021

Many studies are undertaken into nuclear power plants (NPPs) in preparation for accidents exceeding design standards. In this paper, we analyze the applicability of various wireless communication technologies as accident countermeasures in different NPP environments. In particular, a commercial wireless communication module (WCM) is investigated by measuring leakage current and packet error rate (PER), which vary depending on the intensity of incident radiation on the module, by testing at a Co-60 gamma-ray irradiation facility. The experimental results show that the WCMs continued to operate after total doses of 940 and 1097 Gy, with PERs of 3.6% and 0.8%, when exposed to irradiation dose rates of 185 and 486 Gy/h, respectively. In short, the lower irradiation dose rate decreased the performance of WCMs more than the higher dose rate. In experiments comparing the two communication protocols of request/response and one-way, the WCMs survived up to 997 and 1177 Gy, with PERs of 2% and 0%, respectively. Since the request/response protocol uses both the transmitter and the receiver, while the one-way protocol uses only the transmitter, then the electronic system on the side of the receiver is more vulnerable to radiation effects. From our experiments, the tested module is expected to be used for design-based accidents (DBAs) of "Category A" type, and has confirmed the possibility of using wireless communication systems in NPPs.

• Proceedings of the IEEK Conference
• /
• 1999.06a
• /
• pp.57-60
• /
• 1999

In many radio communication environments, there is a special component, called inter-symbol interference (ISI), mused by multipath time delay of signal and ISI components impose limitation of the data transmission rate. In this paper, we consider signaling pulse shapes, called partial response signaling (PRS), for minimizing the effect of ISI and show the improvement of performance by applying one of the partial-response signaling (PRS) pulses to two types of receiver system under dependent noise environments through the Monte-Carlo computer simulations.

• The Journal of the Acoustical Society of Korea
• /
• v.24 no.2E
• /
• pp.61-66
• /
• 2005

Experimental work in underwater acoustic communications using passive phase conjugation has shown that the demodulation error depends on the relative drift rate between the source and receiver [Rouseff et al., IEEE J. Oceanic Eng. 26, 821-831 (2001)]. The observed effect involves the mismatch between the initial impulse response and the subsequent response after the source or receiver has changed locations. In the present work, the effect of drifting source is analyzed by numerical simulations and compared to the experimental results. The communications bit error rate is qualified as a function of drift rate, drifting direction, and source-receiver range.

• The Journal of Industrial Distribution & Business
• /
• v.10 no.7
• /
• pp.83-89
• /
• 2019

Purpose - It is a very important issue for the Korean tourism industry to increase tourism revenue by attracting foreign tourists. Although Japanese tourists have been an important part of the Korean tourism industry for a long time, the level of tourist satisfaction including accommodation has been at the worst compared to other foreign visitors, which strongly requires concrete solutions. Therefore, this study focuses on improving the satisfaction level of Japanese visitors in the use of accommodation, and find out the influence of the managerial response. Research design, data, and methodology - In this study, customer review and managerial response of hotels in Seoul were collected from "Rakuten Travel" which is the most representative online travel agency in Japan. As a result of collecting data from 2016 to 2018, 6,190 customer reviews and 1,241 managerial responses from 120 hotels were used for analysis. In addition, information on the properties of 120 hotels, such as the number of rooms, classification, types of hotel facilities, types of room facilities, accessibility and prices, were collected. To test the hypotheses, moderated multiple regression analysis was conducted with SPSS 22.0. Results - It was found that only 25 sites, 20.8% of the total 120 sites, were implementing managerial response and average response rate was 66.42% among them. As a result of examining the main effects of the hotel attributes on the ratings, accessibility and price are confirmed as effective variables. We also found that the response rate has a significant moderate effect in both the accessibility and price. In other words, there was a significant difference in the influence of accessibility and price on the ratings depending on the response rate. Also, it was confirmed that the response rate is not a pure moderator variable but a quasi moderator variable. Overall, the evidences partially supported the hypothesis. Conclusion - It was possible to provide important suggestions to the hotel managers who were concerned about managing tourist satisfaction with accessibility problems. It was found that the accessibility problem could be overcome by increasing the response rate. It was also confirmed that high ratings can be more effectively achieved for high priced hotels by increasing the response rate.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.16 no.1
• /
• pp.93-98
• /
• 2020

Research on underwater sensor networks is increasing due to such reasons as marine resource management, maritime disaster prediction and military protection. Many underwater sensor networks performs wireless communication using an acoustic sound wave band signal having a relatively low frequency. So the digital part of their modem can take charge of carrier band signal processing. To enable this, the sampling rate of the baseband band signal should be increased to a sampling rate at which carrier band signal processing is possible. In this paper, we designed a sampling rate increasing circuit based on a CIC interpolator for underwater sensor nodes. The CIC interpolator has a simple circuit structure. However, since the CIC interpolator has a large attenuation of the pass band and a wide transition band, an inverse sinc LPF is added to compensate for frequency response of the CIC interpolator. The proposed interpolator was verified in time domain and frequency domain using ModelSim and Matlab.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.15 no.3
• /
• pp.137-141
• /
• 2015

Mobile cloud computing uses cloud service to solve the resource constraint problem of mobile devices. Offloading means that a task executed on the mobile device commits to cloud and many studies related to the energy consumption have been researched. In this paper, we designed a response time model considering sensing data synchronization to estimate the efficiency of the offloading scheme in terms of the response time. The proposed model considers synchronization of required sensing data to improve the accuracy of response time estimation when cloud processes the task requested from a mobile device. We found that the response time is effected by new sensing data generation rate and synchronization period through simulation results.

• The Journal of the Korea Contents Association
• /
• v.14 no.5
• /
• pp.390-402
• /
• 2014

This study, based upon the Sturges' crisis stages, examines the crisis response communication strategies of Korea Professional Football League(KPFL) for the K-league match-fixing case as well as the frequency of related news articles and the source of information. To explore the crisis response communication strategies the Korea Professional Football League used, a total of 118 news articles were analyzed using the content analysis and frequency analysis. The unit of analysis for crisis response communication strategies is sentence. The frequency of news articles based upon the crisis stages shows highest rate at the acute crisis stage. The source of information for news reports shows that KPFL was one of the major sources of the news reports. KPFL's crisis response communication strategy throughout all stages of the crisis stage shows that corrective action strategy was used highest ratio. In particular, the crisis response communication strategy between team, player and KPFL was shown lack of consistency throughout all crisis stages. Implication and future research direction for the results are discussed.

• Therapeutic Science for Rehabilitation
• /
• v.8 no.4
• /
• pp.53-63
• /
• 2019

Objective : Many communication recovery strategies should be used when communication breakdowns occur for successful communication, however, communication problems increase due to inadequate use of such strategies in older people with dementia. The purpose of this study was to investigate the difference of recovery strategy between dementia and the elderly in conversational discourse. Method : The subjects were eight of Alzheimer's dementia and 10 general elderly. Conversation discourse tasks were conducted face-to-face with the subjects. Communication breakdown and communication recovery strategies were analyzed based on 200 utterances collected in the conversation discourse. Result : First, the AD group had more communication breakdown than the control group, but the recovery rate did not differ between the groups. Second, in the AD group, the nonspecific recovery strategy and the clarification demand strategy were used as the expression strategy. The recovery rate after using expressive strategy was more than 90% in explanation strategy, combined strategy, nonspecific repair strategy, and repetition confirmation strategy. The response strategy used a lot of paraphrase strategy and combined strategies, and the recovery rate after using the response strategy was 100% for the simplification strategy, repeat strategy and gesture strategy. Conclusion : The AD group showed more breakdown of research subjects and breakdown of researchers than control group, and it showed ability to use various expression strategy and response strategy though there was difference in repair rate between communication repair strategy. AD group used nonspecific repair strategy in expression strategy the most and paraphrase strategy in response strategy the most. This shows different characteristic from ordinary elderly people. Therefore, it is necessary to utilize this repair strategy for rehabilitation of AD elderly.

• Journal of applied mathematics & informatics
• /
• v.41 no.4
• /
• pp.861-868
• /
• 2023

Nonlinear network creates complex homotopy structural communication in wireless network medium because of complex distribution approach. Due to this multicast topological connection structure, the queuing probability was non regular principles to create routing structures. To resolve this problem, we propose a Co-cluster homotopy queuing model (Co-CHQT) for Nonlinear Algebraic Topological Structure (NLTS-) for improving poison distribution network communication. Initially this collects the routing propagation based on Nonlinear Distance Theory (NLDT) to estimate the nearest neighbor network nodes undernon linear at x_(a,b)→ax²+bx² = c. Then Quillen Network Decomposition Theorem (QNDT) was applied to sustain the non-regular routing propagation to create cluster path. Each cluster be form with co variance structure based on Two unicast 2(n+1)-Z2(n+1)-Z network. Based on the poison distribution theory X_(a,b) ≠ µ(C), at number of distribution routing strategies weights are estimated based on node response rate. Deriving shorte;'l/st path from behavioral of the node response, Hilbert -Krylov subspace clustering estimates the Cluster Head (CH) to the routing head. This solves the approximation routing strategy from the nonlinear communication depending on Max- equivalence theory (Max-T). This proposed system improves communication to construction topological cluster based on optimized level to produce better performance in distance theory, throughput latency in non-variation delay tolerant.