• 제어로봇시스템학회논문지
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• 제4권1호
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• pp.113-122
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• 1998

This paper presents an implementation method of Profibus interface software using FMS(Fieldbus Message Specification). The Profibus interface software is implemented on PC which is widely used as an industrial computer as well as a commercial embedded controller called IUC(Intelligent Universal Controller). In order to enable the Profibus interface software to handle many application tasks and communication services, two kinds of real-time/multi-tasking operating system, OS-9 and CTask, are utilized. We also develop an experimental model of Profibus-based automation system, and evaluate the performance of the Profibus network. Through experiments, the user layer level message latency is measured with respect to the change of message length, message generation interval and TRT(Target Rotation Time). The results of experiment are compared with those of a simulation model which comprises only the physical and data link layers of Profibus. The results of this study shows that the message latency in the user layer level occupies fairly a large part of the total message latency.

• 동아시아식생활학회지
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• 제27권4호
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• pp.442-449
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• 2017

Adenophora triphylla var. japonica extract has been reported to have estrogenic activity and beneficial effects in postmenopausal women requiring estrogen replacement therapy. This study investigated the effects of A. triphylla extract on cognitive function in ovariectomized mice. Water extracts from A. triphylla were administrated to ovariectomized mice fed a high fat diet for 6 weeks. The step through latency time in the passive avoidance test was shortened in ovariectomized mice as compared with sham-operated mice. However, administration of A. triphylla extracts had a tendency to prolong the latency time in ovariectomized mice. Moreover, A. triphylla supplementation caused a significant decrease in mean escape latency in the water maze test. These results indicate that A. triphylla could be used to improve estrogen deficiency-related learning and memory impairments in postmenopausal women.

• ETRI Journal
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• 제38권5호
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• pp.847-857
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• 2016

Broadcasting services such as multi/single channel HDTV and 3DTV/2DTV use a multi-channel encoder that changes the bitrate and composition of the video service depending on the time. However, this type of multi-channel encoder could cause a longer latency owing to the variable bitrate and relatively bigger size of the buffers, which results in the same delay as in 3DTV even for a conventional DTV service. On the other hand, systems built based on separate encoders, each of which is optimized for the target service, might not have such latency problems. Nevertheless, there might be a distortion problem in the image and sound at the time of a switchover between two encoders with different output bitrates and group of picture structures. This paper proposes a system that can realize a seamless video service conversion using two different video encoders optimized for each video service. An overall functional description of the video service change control server, which is a main control block for the proposed system, is also provided. The experiment results confirm the seamless switchover and reduced broadcasting latency of DTV services compared with a broadcasting system composed of a multi-channel encoder system.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2014년도 추계학술대회
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• pp.350-353
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• 2014

클라우드 기반의 주식 체결 시스템에서는 대규모의 데이터가 운영되고 있다. 그러나 주식 체결 시스템에서 클라우드 기반으로 데이터 상호운용은 쉽지 않은 기술이다. 또한 시스템상의 최적의 전송속도와 데이터 적시성을 만족하기에는 어려움이 따른다. 그로 인한 저지연 최소화 문제와 처리 속도 향상을 위한 다양한 기술이 도입되고 있다. 하지만 Socket Direct Protocol, TCP/IP Offload Engine과 같은 하드웨어로는 속도 개선의 한계가 있으며, 도입 효과 또한 낮다는 것이 현실이다. 본 논문에서는 클라우드 환경의 XMDR-DAI 기반 주식 체결 시스템 제안하여 데이터 적시성을 만족하고, 최적의 전송 속도와 신뢰성을 만족하기 위해 Safe Proper Time 방식을 제안한다.

• International Journal of Internet, Broadcasting and Communication
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• 제14권3호
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• pp.276-284
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• 2022

In this paper, we implemented cloud rendering using WebRTC for high-quality AR and VR services. Cloud rendering is an applied technology of cloud computing. It efficiently handles the rendering of large volumes of 3D content. The conventional VR and AR service is a method of downloading 3D content. The download time is delayed as the 3D content capacity increases. Cloud rendering is a streaming method according to the user's point of view. Therefore, stable service is possible regardless of the 3D content capacity. In this paper, we implemented cloud rendering using WebRTC and analyzed its performance. We compared latency of 100MB, 300MB, and 500MB 3D AR content in 100Mbps and 300Mbps internet environments. As a result of the analysis, cloud rendering showed stable latency regardless of data volume. On the other hand, the conventional method showed an increase in latency as the data volume increased. The results of this paper quantitatively evaluate the stability of cloud rendering. This is expected to contribute to high-quality VR and AR services

• 한국멀티미디어학회논문지
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• 제18권5호
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• pp.620-630
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• 2015

This research suggests a load balancing method for a volume rendering system which supports concurrent users. When concurrent users use a volume rendering server system, the computational resources are occupied by a particular user by turns because each process consumes the computational resources as much as possible. In this case, the previous method shows acceptable throughput but the latency is increased for each user. In this research, we suggest a method to improve the latency without performance degradation. Each process makes concessions for taking the resources according to the number of users connected to the system. And we propose a load balancing method in the dynamic situation in which the number of users can vary. Using our methods, we can improve the latency time for each user.

• 전자공학회논문지S
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• 제34S권12호
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• pp.60-69
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• 1997

We present an average method based on the multirate signal processing and dynamic allocation average for the purpose of monitoring event-related potentials(ERP) and continuously and dynamically. In the proposed method, first, latency shifts are detected through the cross correlation between a current response and the reference response. Then, the multirate signal processing which is composed of up-sampler, lowpass filter, and down sampler is performed to compensate the latency shifts of the reference response, therefore we obtain the reference response with a peak latencies compenated by those of a current response. Finally, the single response is obtained by averaging the compensated reference response and a current response. In the simulation, the results of quantitative evaluation by simulation and the results using linical data are presented. From the result, the proposed method reflects dynamic time-varying ERP more exactly than previous methods and is also effective in consecutive monitoring of ERP.

• 수면정신생리
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• 제18권2호
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• pp.67-71
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• 2011

Schizophrenia is a chronic, currently incurable, and devastating syndrome. Although sleep disturbances are not primary symptoms of schizophrenia, they are important aspects of schizophrenia. Difficulties initiating or maintaining sleep are frequently encountered in patients with schizophrenia. Many schizophrenics report low subjective sleep quality. Measured by polysomnography, increased sleep latency as well as reduced total sleep time, sleep efficiency, slow wave sleep, and rapid eye movement sleep latency (REM latency), are found in most patients with schizophrenia and appear to be an important aspect of the pathophysiology of this disorder. Some literatures suggest that worsening sleep quality precedes schizophrenic exacerbations. Co-morbid sleep disorders such as obstructive sleep apnea (OSA) and restless legs syndrome (RLS), and sleep-disrupting behaviors associated with schizophrenia may lead to sleep disturbances. Clinicians should screen the patient with sleep complaints for primary sleep disorders like OSA and RLS, and carefully evaluate sleep hygiene behaviors of all patients with schizophrenia who complain of sleep disturbances.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2004년도 가을 학술발표논문집 Vol.31 No.2 (3)
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• pp.685-687
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• 2004

본 논문에서는 이동 인터넷 환경에서 핸드오프 시, 링크 계층 (L2) 정보를 이용하며 새로 발견한 모바일 에이전트와의 등록 절차를 L2 핸드오프 완료 후 곧바로 수행하는 로우-레이턴시 (Low-Latency) 핸드오프 방안을 제안하고 이를 구현한다. 제안한 방법은 기존 연구들에 비해 추가적인 L2 핸드오프 지연 및 별도 네트워크 구성요소를 필요로 하지 않으며 보다 일반적이고 현실적인 네트워크 환경에서 적용될 수 있는 방안이다. 실험 결과는 제안된 방법이 인프라스트럭처 (infrastructure) 모드로 설정된 무선 랜에서 모바일 IP의 핸드오프 지연을 크게 개선하여 이동 인터넷 환경의 실시간 멀티미디어 서비스에 적합함을 보여준다.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2012년도 춘계학술발표대회
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• pp.607-608
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• 2012

Data aggregation is a fundamental problem in wireless sensor networks which attracts great attention in recent years. Delay and energy efficiencies are two crucial issues of designing a data aggregation scheme. In this paper, we propose a distributed, energy efficient algorithm for collecting data from all sensor nodes with the minimum latency called Delay-aware Power-efficient Data Aggregation algorithm (DPDA). The DPDA algorithm minimizes the latency in data collection process by building a time efficient data aggregation network structure. It also saves sensor energy by decreasing node transmission distances. Energy is also well-balanced between sensors to achieve acceptable network lifetime. From intensive experiments, the DPDA scheme could significantly decrease the data collection latency and obtain reasonable network lifetime compared with other approaches.