• 한국경영과학회:학술대회논문집
• /
• 대한산업공학회/한국경영과학회 2006년도 춘계공동학술대회 논문집
• /
• pp.1656-1660
• /
• 2006

Distributed coordination function(DCF) is the primary random access mechanism of IEEE 802.11, which is the basic protocol of wireless LAN based on the CSMA/CA protocol. It enables fast installation with minimal management and maintenance costs and is a very robust protocol for the best effort service in wireless medium. The current DCF, however, is known to be unsuitable for real-time applications such as voice message transmission. In this paper, we focus on the performance issues of IEEE 802.11 which accommodate the prioritized messages. Existing results use the initial window size and backoff window-increasing factor as tools to handle the priority of the messages. Instead, we introduce a novel scheme which chooses the backoff timer with arbitrary probabilities. By this, one can greatly reduce the backoff delay of the lower priority messages without degrading the performance of higher priority.

• Journal of Advanced Marine Engineering and Technology
• /
• 제28권2호
• /
• pp.347-353
• /
• 2004

Neural oscillator can be applied to oscillator systems such as analysis of image information, voice recognition and etc, Conventional learning algorithms(Neural Network or EBPA(Error Back Propagation Algorithm)) are not proper for oscillatory systems with the complicate input patterns because of its too much complex structure. However, these problems can be easily solved by using a synchrony characteristic of neural oscillator with PLL(phase locked loop) function and a simple Hebbian learning rule, Therefore, in this paper, it will introduce an technique for Recognition of the Korean Character using Phase Synchronization Neural Oscillator and will show the result of simulation.

• 대한수학회논문집
• /
• 제14권2호
• /
• pp.405-423
• /
• 1999

We consider a statistical multiplexer model with finite buffer capacity and finite number of independent identical 3-state bursty voice sources. The burstiness of the sources is modeled by describing both two different active periods (at the rate of one packet perslot) and the passive periods during which no packets are generated. Assuming a mixture of two geometric distributions for active period and a geometric distribution for passive period and geometric distribution for passive period, we derive the recursive algorithm for the probability mass function of the buffer contents (in packets). We also obtain loss probability and the distribution of packet delay. Numerical results show that the system performance deteriorates considerably as the variance of the active period increases. Also, we see that the loss probability of 2-state Markov models is less than that of 3-state Markov models.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1990년도 하계학술대회 논문집
• /
• pp.47-50
• /
• 1990

Deafs cannot speak straight voice as normal people in lack of feedback of their pronunciation, therefore speech training is required. In this study, fundamental frequency, intensity, formant frequencies, vocal tract graphic and vocal tract area function, extracted from speech signal, are used as feature parameter. AR model, whose coefficients are extracted using inverse filtering. is used as speech generation model. In connect ion between vocal tract graphic and speech parameter, articulation distances and articulation distance functions in selected 15-intervals are determined by extracted vocal tract areas and formant frequencies.

• 대한음성언어의학회:학술대회논문집
• /
• 대한음성언어의학회 1996년도 제6회 학술대회 심포지움
• /
• pp.79-79
• /
• 1996

최근 들어 음성에 대한 일반인들의 관심이 높아지면서 음성이상을 호소하며 이비인후과 외래를 방문하는 환자가 점차적으로 증가하는 추세에 있다. 그러나 이러한 음성이상을 객관적으로 평가할 수 있는 기준이 국내에는 거의 없는 실정이다. 이에 저자들은 본 연구에서 기왕력 상 폐질환이나 신경계질환, 후두질환을 앓은 적이 없으며 음성조율 기관에 이상이 없고 정상적인 청력을 가진 10세에서 69세까지의 무작위 추출된 정상 한국인 남자 112명과 여자 122명을 대상으로 Aerophone II voice function analyzer를 이용하여 공기역동학적 검사 중 최대발성지속시간(maximum phonation time), 평균호기류율(mean airflow rate), 발성율(phonation quotient), 발성시 기류량(phonatory flow volume) 및 성문하압(subglottal pressure)의 정상 한국인의 남녀 년령별 평균치를 측정하고자 하였다. (중략)

• 대한후두음성언어의학회지
• /
• 제21권1호
• /
• pp.22-26
• /
• 2010

Neuromuscular Disorders Affecting the Larynx are steadily important topics at laryngology. Physiology of larynx is controlled by the frame structure and neuromuscular dynamics to acting on the specialized soft tissue, Therefore, for a proper understanding of the larynx, it is needed the voice and swallowing, a series of prayers on the regulation of neurologic function and the correlation between systemic neuromuscular disease and laryngeal symptoms and clinical knowledge, We described that clinical findings and treatments of the 3 neurological diseases causing dysphonia well (Parkinson's disease, laryngeal tremor, spasmodic dysphonia) and vocal impairments for stoke patients.

• 한국통신학회논문지
• /
• 제23권9A호
• /
• pp.2131-2140
• /
• 1998

Signal-to-interference ratio (SIR)-based dynamic code allocation method to be rioritized for handoff call is proposed and evaluated in a direct sequence-code division multiple access (DS-CDMA) cellular systm. Proposed method allocates a code to a mobile terminal according to the restidual capacity computed by SIR in the base station. We consider the voice activity detection to increase the system capacity. We evaluate the performance of proposed method with computer simulation. And the handoff decision function that controls handoff of mobile terminal is interodcued. The proposed method provide much improvement in the forced termination probability and handoff call fail probability.

• 대한안전경영과학회지
• /
• 제1권1호
• /
• pp.101-110
• /
• 1999

QFD is a market driven design and development methodology for products and services to meet or exceed customer's needs and expectations, This method enables to specify clearly the customer's needs and then evaluate the product capability in terms of its impact on meeting those needs. Process of satisfying customers begins with effectively soliciting their different needs and wants which may be non-technical and imprecise in nature. Although the HoQ is a comprehensive tool for showing the relationships between attributes, it lacks the flexibility to deal with the inherent inexactness and vagueness in the voice of customer. In this paper, fuzzy theory is introduced to overcome this limitation. Qualitative customer requirements are interpreted quantitative data through fuzzy inference procedure, and then target value is determined.

• 대한안전경영과학회:학술대회논문집
• /
• 대한안전경영과학회 2010년도 춘계학술대회
• /
• pp.347-357
• /
• 2010

본 논문은 QFD(Quality Function Development)기법을 활용하여 소비자의 요구사항을 반영한 음식물 처리기의 핵심 품질 요소를 도출하는데 목적을 두었다. 일반 소비자와 관련업계 종사자를 대상으로 설문조사와 FGI를 실시하여 VOC(voice of customer)를 도출하였고, 전문가 그룹을 통해 EC를 도출하여 VOC와 EC(Engineering Characteristic)간의 상관관계를 도표화 하여 HOQ(House Of Quality)를 작성하였다. HOQ 차트를 통해 분쇄건조식 음식물 처리기에 있어 우선시 되는 것은 음식물 분쇄기능, 건조기능 외에 냄새 배출기능, 외관 색상 등의 요소가 중요한 품질요인이라는 결과을 도출하였다. 부품별 요인으로는 분쇄 탈수와 관련 된 모터와 냄새 제거와 관련한 팬모터가 가장 핵심 부품으로 고려되어야 한다는 결과를 도출하였다.

• 대한기관식도과학회지
• /
• 제19권1호
• /
• pp.5-10
• /
• 2013

Bilateral vocal cord palsy (BVCP) present a challenging condition which result from various etiologies including iatrogenic recurrent laryngeal nerve injury, progressive neurological disorder, intubation, trauma, tumor and idiopathic cause. Careful history taking, laryngoscopic evaluation, laryngeal EMG, and imaging studies are helpful for providing a precise diagnosis and planning appropriate treatment. BVCP causes airway restriction and not vocal dysfunction. In patients with BVFP, treatment is directed at maximizing the airway, while attempting to limit the negative effects of treatment on vocal function. A variety of surgical procedures are available for mangement of BVCP. The most conservative, limited procedure should be selected initially, and then further surgery and more extensive surgery can be tailored to the patient's airway and voice needs. This review will address the etiology, diagnosis, and managements of BVCP.