• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 ICEIC The International Conference on Electronics Informations and Communications
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• pp.249-253
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• 2004

Wavelet transform (WT) has attracted most engineers and scientists because of its excellent properties. The coherence of practical approach and a theoretical basis not only solves currently important problems, but also gives the potential of formulating and solving completely new problems. It has been show that multi-resolution analysis of Wavelet transforms is good solution in speech analysis and threshold of wavelet coefficients has near optimal noise reduction property for many classes of signals. This paper proposed applications of wavelet in speech processing: pitch detection, voice-unvoice (V -UV) decision, denoising with the detailed algorithms and results.

• JSTS:Journal of Semiconductor Technology and Science
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• 제15권1호
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• pp.122-130
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• 2015

This paper presents a 6 Gb/s 4-channel arrayed transimpedance amplifiers (TIA) with the gain control for 4-channel passive optical network in $0.13{\mu}m$ complementary metal oxide semiconductor (CMOS) technology. A regulated cascode input stage and inductive-series peaking are proposed in order to increase the bandwidth. Also, a variable gain control is implemented to provide flexibility to the overall system. The TIA has a maximum $98.1dB{\Omega}$ gain and an input current noise level of about 37.8 pA/Hz. The die area of the fabricated TIA is $1.9mm{\times}2.2mm$ for 4-channel. The power dissipation is 47.64 mW/1ch.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권8호
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• pp.2736-2750
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• 2022

As demands for the maritime communications increase, a variety of functions and information are required to exchange via elements of maritime systems, which leads communication traffic increases in maritime frequency bands, especially in VHF (Very High Frequency) band. Thus, effective resource management is crucial to the future maritime communication systems not only to the typical terrestrial communication systems. VHF data exchange system (VDES) enables to utilize more flexible configuration according to the communication condition. This paper focuses on the VDES communication system among VDES terminals such as shore stations, ship stations and aids to navigation (AtoN) to address efficient resource allocation. We propose a resource management method considering a MIMO (Multiple Input Multiple Output) technique in VDES, which has been widely used for modern terrestrial wireless networks but not for marine environments by scheduling the essential communication resources. We introduce the general channel model in marine environment and give two metrics, spectral and the energy efficiencies to examine our resource scheduling algorithm. Based on the simulation results and analysis, the proposed method provides a possibility to enhance spectral and energy efficiencies. Additionally, we present a trade-off relationship between spectral and energy efficiencies. Furthermore, we examine the resource efficiencies related to the imperfect channel estimation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.520-523
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• 2004

A phase-locked loop control system designed by using the linear quadratic regulator approach is presented in this paper. The system thus designed is optimal system when system is in locked state and the parameter value of loop filter which is an active PI filter can be obtained easily. By considering the structure of loop filter of phase-locked loop is included in the process to be controlled, a type 1 servo system can be constructed when voltage control oscillator is considered as an integrator. The integral gain of the proposed system obtained by linear quadratic regulator approach can be used as an optimal value to design the parameter of loop filter. The implemented result in controlling the second-order lag pressure process by using the proposed scheme show that the system response is fast with no overshoot and no steady-state error. Furthermore, the experimental results are also shown in term of output disturbance effect rejection, tracking and process parameter changed.

• 한국도서관정보학회지
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• 제35권1호
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• pp.377-397
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• 2004

This study investigated the use of community information and communication technologies in light of its dual visions (i.e., serving as an affordable Internet service provider and a community building tool). Surveying the randomly selected users of a community network (n = 213), this study examined the influence of the community features on service use compared to that of Internet features. The present study found that the respondents were using the service mainly for general Internet features, such as email and web access. More than two-thirds of the respondents did not recognize community contents as available service. Community features of the service were found as significant predictors of use only among people who were aware of community contents but not among people who were not. Nonetheless, there was no difference in the amount of use between the two groups, indicating that the awareness of community contents itself did not increase use. Findings suggest that the service providers did not fully communicate the community aspect of the service with the users although the very aspect distinguishes the service from other Internet services.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.41-44
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• 2003

We propose portable equipment that monitors current and voltage of high-potential power transmission lines. In the equipment, a current and voltage sensor are attached to an insulator that supports a power transmission line: A clamped to the power line and the detected current signal is transmitted to the ground station by a wireless optical link using transmission line is detected by a high resistance element, zinc oxide (ZnO). That acts as a potential divider between the power line and ground. We make an experimental device for 66kV power line and demonstrate that it can monitor currents proposed equipment is small-sized, light, and inexpensive in comparison with the conventional CT (current transformer) and PT (potential transformer) since it does not require high potential insulators and magnetic cores, further, the equipment is easily installed owing to its small size and its simple structure.

• 한국정보시스템학회:학술대회논문집
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• 한국정보시스템학회 2004년도 춘계학술대회
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• pp.202-213
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• 2004

An effective use of information and communications technology is thought of as critical for achieving corporate competitiveness. This study identifies patterns of corporate use of communications technology, and examines how the use of those technologies is associated with business strategies and the level of information intensity. A survey study on a sample of Korean corporations shows that the use of communications technology is closely related both to business strategy and information intensity, and that communications technologies can be divided into two types in terms of their usage pattern. The structured communication technology is found to be related to the tools and services that support structured tasks, and the The unstructured technology to the tools the use of which is less structured and more flexible. Cost-based strategy is found to be closely related to the use of structured communication technology, while differentiation strategy is closely related to the use of unstructured communication technology.

• 전기전자학회논문지
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• 제25권1호
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• pp.193-200
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• 2021

불법어업 방지와 유실어구 저감을 위해 해양환경에서 상시적이고 연속적인 어구 모니터링 시스템 개발이 필요하며, 본 논문에서는 수산자원 고갈로 점차 어로활동 범위가 넓어지는 현실과 열악한 해상환경을 고려한 25Km 이상의 통신 커버리지를 갖는 장기적 운용 가능한 신뢰성 있는 시스템 모델을 설계하고, 설계결과를 구현하여 14Km 떨어진 해상환경에 부이와 무선노드를 각각 설치하여 상용망과 Private LoRa망을 통한 통신 성공률을 구분 확인하고 수집된 위치정보를 통한 각 관제시스템의 관제기능을 확인함으로써 시스템의 운용 가능성을 검증하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권10호
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• pp.4698-4716
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• 2017

Wireless signal transmission is influenced by environmental effects. These effects have also been challenging for Vehicular Ad hoc Network (VANET) in real-time communication. More specifically, in an urban environment, with high mobility among vehicles, a vehicle's status from the transmitter can instantly trigger from line of sight to non-line of sight, which may cause loss of real-time communication. In order to overcome this, a deterministic signal propagation model is required, which has less complexity and more feasibility of implementation. Hence, we propose a realistic path loss model which adopts ray tracing technique for VANET in a grid urban environment with less computational complexity. To evaluate the model, it is applied to a vehicular simulation scenario. The results obtained are compared with different path loss models in the same scenario based on path loss value and application layer performance analysis. The proposed path loss model provides higher loss value in dB compared to other models. Nevertheless, the performance of vehicle-vehicle communication, which is evaluated by the packet delivery ratio with different vehicle transmitter density verifies improvement in real-time vehicle-vehicle communication. In conclusion, we present a realistic path loss model that improves vehicle-vehicle wireless real-time communication in the grid urban environment.

• Asian Journal for Public Opinion Research
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• 제9권3호
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• pp.293-306
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• 2021

The news and views of Pakistani television channels are extensively shared on digital media for information or analysis where the general public discusses overt and covert agendas by mentioning their factual and presentational style. This study contributes to the contemporary studies of media perception through focus group interviews with 72 randomly selected master's and bachelor's students studying Media and Communication at the School of Media and Communication Studies, University of Management and Technology, Lahore, Pakistan to provide information about the feelings and observations of future journalists and media literates. In summary, the findings of our research exposed the negative perception of Pakistani electronic media among the participants due to what they perceived as biased, inaccurate, and unethical reporting.