• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.11
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• pp.1077-1082
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• 2016

IDS can be used as a countermeasure for malicious attacks which cause degrade of network transmission performance by disturbing of MANET routing function. In this paper, effects of IDS for transmission performance on MANET under grayhole attacks which has intrusion objects for a part of transmissions packets, some suggestion for effective IDS will be considered. Computer simulation based on NS-2 is used for performance analysis, performance is measured with VoIP(: Voice over Internet Protocol) as an application service. MOS(: Mean Opinion Score), CCR(: Call Connection Rate) and end-to-end delay is used for performance parameter as standard transmission quality factor for voice transmission.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.8B
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• pp.620-629
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• 2012

This paper proposes packet aggregation scheme for considering energy consumption of mobile devices on guaranteeing quality of voice. To our purpose, we analyze VoIP service on wireless multi-hop channel in terms of delay, packet loss and energy consumption when packet aggregation scheme is applied to VoIP service. Moreover, we induce a cost function with considering of tradeoff relation between quality of voice and energy consumption.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1983.05a
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• pp.14.2-14
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• 1983

Complications and sequelae of the laryngeal trauma are respiratory difficulties, edema or swelling, cellulitis or abscess, fistula, perichondrium and chondritis, chronic laryngeal stenosis, vocal cord paralysis, decannulation difficulty, and impaired voice production etc. Generally, the treatment of laryngeal injuries consists of initial tracheostomy for adequate airway and later surgical intervention for its complications and sequelae. Recently, authors experienced a case of closed laryngeal injury with thyroid cartilage fracture, left vocal cord paralysis, swallowing difficulty and right clavicular fracture owing to automobile accident. With reconstructive surgery for thyroid cartilage fracture, we established an adequate airway, improved swallowing function and better voice production.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.5
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• pp.901-906
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• 2006

In this paper, we describe the implementation of the digital photo frame system that displays the images coming through the memory card of a digital camera. Each image can be recorded with voice in this system, and a function of the mp3 player is implemented as well. We use Intel PXA255 to control the system and modify the bootloader and linux kernel. Also we adapt device driver for this system. For the realization of image display, voice recording and mp3 playing in the basis of the linux system, we program some of the Microwindows system configuration files and program applications here. This study will be a good example to access the development of the digital photo frame based on the linux system using less-power and high performed embedded processor.

• Journal of Korea Multimedia Society
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• v.24 no.7
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• pp.913-921
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• 2021

After arranging the general usability evaluation criteria of existing VUI researchers, this study verified how appropriate these criteria are for AI VUI specialized in navigation and the priority of their suitability. The VUI used in this study was analyzed through a survey from a total of 195 Chinese users after analyzing the navigation VUI used in China. As a result of the analysis, the usability evaluation criteria of the navigation VUI were extracted from three sub-factors of 'task accuracy', 'function satisfaction', and 'information reliability' in verifying conformance with general VUI evaluation criteria. With the recent advent of self-driving cars, safety and response speed are becoming very important, so Chinese users also ranked responsiveness as the top priority in VUI design, and the importance was also found to be high. Also, both men and women have the highest reactivity and the lowest multiplicity. VUI requires a convenient and natural interface to understand the intention between two objects through usability evaluation and verification in order to have effective interaction between humans and machines.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.6
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• pp.1181-1186
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• 2022

In this study, we have researched for a high-efficiency display with low power, less complicated configuration, and more attractive features than using conventional displays (CRT, LCD, LED, etc.) by manufacturing a propeller display using the POV(Persistence of Vision) phenomenon. After setting the reference point using the Hall sensor, the channel recognition signal and voice recognition signal are transmitted to the display using Bluetooth through the mobile phone application created based on the App program, and the display performs different operations according to the commanded Bluetooth signal. Finally, it was confirmed that the desired information is expressed on the display screen at a motor speed of 1,030 rpm.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.1
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• pp.71-78
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• 2009

Sound source localization systems in service robot applications estimate the direction of a human voice. Time delay information obtained from a few separate microphones is widely used for the estimation of the sound direction. Correlation is computed in order to calculate the time delay between two signals. In addition, PHAT weighting function can be applied to significantly improve the accuracy of the estimation. However, FFT and IFFT operations in the PHAT weighting function occupy more than half of the area of the sound source localization system. Thus efficient FFT and IFFT designs are essential for the IP implementation of sound source localization system. In this paper, we propose an efficient FFT/IFFT design method based on the characteristics of human voice.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.1B
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• pp.71-76
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• 2000

On multimedia teleconferencing system existing a number of participants, face of the participants can beperceived by visual image. However, differentiation of each participant's voice and spaciousness sense are very hard since voice of all participants is processed with one dimensional data. In this paper, we implemented three dimensional audio rendering system using the HRTF(Head Related Transfer Function) and distance sense reproduction method and determined the optimal location of the participants for teleconferencing system. In the results of the listening test using elevation and azimuth angle, we showed that directional perception of the azimuth angles were better than that of the elevation angles. Specially, we showed that participant location using the HRTFS of the azimuth angle 10" , 90" , 270" and350" was efficient in teleconferencing system existing four participants. We also proposed that distance cue was used for enhancement of the reality and location of many participants more than five.ipants more than five.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.2
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• pp.111-118
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• 2008

In this paper a novel medium access control mechanism is investigated as a means to support real-time services. The primary goal is to provide constant-bit-rate voice call services to pairs of autonomous mobile nodes operating in ad hoc networks. Here, a time-slot reservation based MAC is considered to provide real-time voice calls and a new MAC called the time-slot reservation coordination function(TRCF) is presented. In addition to this isochronous type MAC protocol development, the proposed protocol is modeled using a Markov chain in order to predict its behavior. The performance of TRCF is analytically derived and the performance measures such as average wait time taken for a call connection and throughput are obtained.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.5
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• pp.861-868
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• 2010

As CAS, X-ATK, and INT models considered as the most typical Air-to-Ground operation models in ROKAF are mainly designed as the voice-centered system between aircraft and ground control facilities, it is critical to newly develop the Link-16 based model for the ROK-US combined operation between F-15K, AWACS, M-SAM, and KDX-III equipped with Link-16. Former studies had been limited to the CAS operation, and they had mainly focused on reducing the voice transmission time to exchange the information between each mission step with maintaining existing operation steps. Therefore, this paper makes up the weak point in former studies, thereby designing new Air-to-Ground operation model for CAS, X-ATK, INT mission using Enterprise Architecture OV6c, which enables both aircraft and ground control facilities or between aircraft to obtain the real-time information on the location, identification, armament and the real-time image data through the broadcasting function. Based on the analysis of new operation model, we come to a conclusion that by simultaneously exchanging the information on mission between nodes concerned through the broadcasting function of Link-16. It is possible to cut down superfluous steps among the mission steps, and to reduce the mission time. It is clear that it gives rise to improve the battle efficiency and the decision-making tempo as well as the battlefield situational awareness.