• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.1A
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• pp.96-103
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• 2000

The voice traffic is one of the most important real-time objects in WATM(Wireless Asynchronous Transfer Mode) networks. In this paper, we propose a new MAC(Medium Access'Control) protocol for the efficienttransmission of voice traffic over WATM networks in the multimedia environment and compare the performanceto existing similar protocols. The new protocol separates the reservation slot period for voice and that for data toguarantee some level of QoS(Quality of Service) in voice traffic. This is denoted by a slot assignment functiondepending on the frame size. According to the characteristics of voice traffic which is repeatedly in silent states,the protocol allocates voice reservation request slots dynamically with respect to the number of silent(off state)voice sources and also sends the first block of talkspurt restarted after silent period with a reservation requestslot to reduce the access delay.The simulation results show that the proposed protocol has better performance than Slotted Aloha in bandwidthefficiency, and can serve a certain level of QoS by the given slot assignment function even when the number ofvoice terminals varies dynamically. This means we can observe that the new MAC protocol is much better thanthe NC-PRMA(None Collision-Packet Reservation Multiple Access) protocol.

• The Journal of Korean Medicine
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• v.26 no.2 s.62
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• pp.77-84
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• 2005

Objectives: Chunghyul-dan is a combinatorial herbal medicine, and previous studies reported it had therapeutic effects for microangiopathy, which is a major part. in the progression of stroke, as well as having anti-hypertensive, anti-hyperlipidemic, anti-apoptotic, anti-oxidative, and anti-inflammatory activities, Therefore, we examined the inhibitory effect of Chunghyul-dan on stroke occurrence in patients with silent brain infarction. Methods: We prescribed Chunghyul-dan at 600 mg a day to patients with silent brain infarction confirmed by brain MRI, and monitored stroke occurrence, drug compliances, and adverse effects for 1 year, We then performed follow-up brain MRI to detect new vascular lesions after 1 year of Chunghyul-dan medication. As for the subjects lost to follow-up, we assessed their prognosis after 1 year by telephone. Results: There were twenty-one subjects who were treated with Chunghyul-dan for more than 1 year, None of them experienced new clinical syndromes characterized by rapidly developing clinical symptoms and signs of focal and at times global loss of brain function, which could be accompanied with evidence of stroke occurrence, or any adverse effects during the Chunghyul-dan medication period. These results might be explained by various biochemical effects of Chunghyul-dan on microangiopathy, which is closely related with cell cycle progression, hypertension, hyperlipidemia, vascular inflammation, and oxidative damage. Of the 10 subjects lost to follow-up, six were reached; two of them had stroke occurrence. Conclusions: We suggest Chunghyul-dan could be useful for prevention of stroke occurrence in patients with silent brain infarction by preventing the progression of microangiopathy. Further study with a randomized controlled trial is needed to confirm this suggestion.

• Journal of Korean Neurosurgical Society
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• v.67 no.1
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• pp.42-49
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• 2024

Objective : There is still controversy regarding whether neck remodeling stent affects the occurrence of silent embolic infarction (SEI) after aneurysm coiling. Thus, the aim of the present study is to investigate the incidence of SEI after stent-assisted coiling (SAC) using Neuroform Atlas Stent (NAS) and possible risk factors. This study also includes a comparison with simple coiling group during the same period to estimate the impact of NAS on the occurrence of SEI. Methods : This study included a total of 96 unruptured intracranial aneurysms in 96 patients treated with SAC using NAS. Correlations of demographic data, aneurysm characteristics, and angiographic parameters with properties of SEI were analyzed. The incidence and characteristics of SEI were investigated in 28 patients who underwent simple coiling during the same period, and the results were compared with the SAC group. Results : In the diffusion-weighted imaging obtained on the 1st day after SAC, a total of 106 SEI lesions were observed in 48 (50%) of 96 patients. Of these 48 patients, 38 (79.2%) had 1-3 lesions. Of 106 lesions, 74 (69.8%) had a diameter less than 3 mm. SEI occurred more frequently in older patients (≥60 years, p=0.013). The volume of SEI was found to be significantly increased in older age (≥60 years, p=0.032), hypertension (p=0.036), and aneurysm size ≥5 mm (p=0.047). The incidence and mean volume of SEI in the SAC group (n=96) were similar to those of the simple coiling group (n=28) during the same period. Conclusion : SEIs are common after NAS-assisted coiling. Their incidence in SAC was comparable to that in simple coiling. They occurred more frequently at an older age. Therefore, the use of NAS in the treatment of unruptured intracranial aneurysm does not seem to be associated with an increased risk of thromboembolic events if antiplatelet premedication has been performed well.

• The KIPS Transactions:PartC
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• v.16C no.5
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• pp.661-668
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• 2009

The Extended real-time Polling Service (ErtPS) is proposed tosupport QoS of VoIP service with silence suppression which generates variable size data packets in IEEE 802.16e systems. If the silence is suppressed, VoIP should support Comfort Noise Generation (CNG) which generates comfort noise for receiver's auditory sense to notify the status of connection to the user. CNG mode in silent-period generates a data with lower bit rate at long packet transmission intervals in comparison with talk-spurt. Therefore, if the ErtPS, which is designed to support service flows that generate data packets on a periodic basis, is applied to silent-period, resources of the uplink are used inefficiently. In this paper, we proposed the Improved ErtPS algorithm for efficient resource utilization of the silent-period in VoIP traffic supporting CNG. In the proposed algorithm, the base station allocates bandwidth depending on the status of voice at the appropriate interval by havingthe user inform the changes of voice status. The Improved ErtPS utilizes the Cannel Quality Information Channel (CQICH) which is an uplink subchannel for delivering quality information of channel to the base station on a periodic basis in 802.16e systems. We evaluated the performance of proposed algorithm using OPNET simulator. We validated that proposed algorithm improves the bandwidth utilization of the uplink and packet transmission latency

• Journal of Chest Surgery
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• v.24 no.5
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• pp.505-509
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• 1991

Rupture or laceration of the aorta is a more common result of nonpenetrating traumatic injury than is generally appreciated. If the lesion is promptly diagnosed, a appropriate surgical treatment may be life-saving. Diagnosis may be difficult and at times the rupture may remain clinically silent for variable period.< A 34 - year old male patient had sustained steering wheel injury to his chest during automobile accident 8 weeks prior to admission. The diagnosis of traumatic aneurysm of the aorta was delayed as he was asymptomatic. Surgical repair of false aneurysm of the descending aorta was successfully performed by partial cardiopulmonary bypass through the femoral artery and vein.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.48 no.5
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• pp.107-116
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• 2011

In this paper, a traffic adaptive sleep based medium access control (TAS-MAC) protocol for wireless sensor networks (WSNs) is proposed. The protocol aims for WSNs which consist of clustered sensor nodes and is based on TDMA-like schema. It is a typical schedule based mechanism which is adopted in previous protocols such as LEACH and Bit-Map Assisted MAC. The proposed MAC, however, considers unexpected long silent period in which sensor nodes have no data input and events do not happen in monitoring environment. With the simple traffic measurement, the TAS-MAC eliminates scheduling phases consuming energy in previous centralized approaches. A frame structure of the protocol includes three periods, investigation (I), transmission (T), and sleep-period (S). Through the I-period, TAS-MAC aggregates current traffic information from each end node and dynamically decide the length of sleep period to avoid energy waste in long silent period. In spite of the energy efficiency of this approach, the delay of data might increase. Thus, we propose an advanced version of TAS-MAC as well, each node in cluster sends one or more data packets to cluster head during the T-period of a frame. Through simulation, the performance in terms of energy consumption and transmission delay is evaluated. By comparing to BMA-MAC, the results indicate the proposed protocol is more energy efficient with tolerable expense in latency, especially in variable traffic situation.

• The Journal of the Korea Contents Association
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• v.16 no.11
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• pp.776-783
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• 2016

Discussion of facial image of the movie starts is recognized as an art movie that started from silent film period. Critical discussions on the facial image initiated with the emergence of 'close-up' are performed in the context to claim the superiority of close-up format. Therefore, the trend of critical discussion on the facial image differs from two perspectives to perceive close-up in this era. The first perspective is to privilege both face and close-up since close-up is recognized as the unique tool to realize the face considering close-up as the independent body to have new aesthetic feasibility of the movie. The second perspective is to consider close-up as one of the plots in the movie language to complete its narration. In this case, it is perceived as just a short, which has no differentiation from the others, as long as the facial image does not interfere the completeness of the narration, because the characteristics of close-up to highlight the subject more than the other short is not recognized as the unique form to complete the movie, and because it has the meaning only when the subject and the format aim to maintain the completeness of the narration.

• The Journal of the Korean dental association
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• v.14 no.12
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• pp.951-967
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• 1976

정상교합인 179명과 , 악관절이상환자 12명, 그리고 악관절이상환자중 국소마취를 한 6명, 총 197예의 대상에 교근의 Jaw-Jerk Reflex를 야기시키기 위하여 Spring Triggered Tapping Device를 하악골유간부에 장치하고, 교근에 쌍극은판전극을 부착하여 Functional Switch Assembly 를 통하여 Preamplifier(461 B형, Beckman)에서 증폭된 활동전압을 Dynograph (RS형 9853A, Beckman)에서 직접 기록하였다. 기록된 근전도는 Computer (Univac 9400 Cobol Complier)로 분석하여 다음과 같은 결론을 얻어 이에 보고하는 바이다. (1) 정상교합인 ; 남자 평균 21msec, 여자 20msec, 남여평군 20±5.99msec (S.D.)였다. (2) 악관절이상환자 : 남자평균 39msec, 여자38msec, 남여평균 39±13.57msec (S.D.) (3) 국소마취를 시행한 악관절이상환자 ; 남자평균 21msec, 여자 18msec, 남여평균 19msec (4) 179명의 정상교합인중 34명은 Masseteric Slient period가 나타나지 않았다. (5) 정상교합인과 악관절이상환자가 중복될 수 있는 기간은 31~33.5msec 였다. (6) 정상교합인과 악관절이상환자와의 경계는 32.2msec 였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.2
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• pp.270-278
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• 1993

This paper is presented the phonetic segmentation alg9rithm of the Korean speech signals which is finded the exact pitch using the super resoluton pitch determination and is compared corss-correlation to threshold each pitch period. The features of the proposed algorithm are infinite resolution and high reliability, and also can separate transient or silent segment. The algorithm is instrumental to speech processing applications which require vector quantization and speech recognition. The presented algorithm is implemented by 386-MATLAB on PC 386/DX and is verified the exact pitch period and the phonetic segmentation of speech signals.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.967-972
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• 2001

An axial fan design code, called iDesignFan$^{TM}$, was developed. In this code, three major loss models were used to predicted the aerodynamic performance of a fan. The overall sound pressure level, predicted from steady blade loading, is also used as an input parameter from the third loop of the designing process to acquire most silent fan for the given aerodynamic performance parameters. With this kind of inverse design concept used in this code, the period of designing a fan, which has given aerodynamic performance with minimal acoustic noise, is significantly shortened. The experimental results of a prototype fan, designed by this code, showed that aerodynamic and acoustic performance of an axial fan is reasonably well predicted. Thus, one can design/develop an axial fan in a short time by using the code.e.