• 대한임베디드공학회논문지
• /
• 제14권4호
• /
• pp.219-226
• /
• 2019

One of the most widely studied protocols for tactical ad-hoc networks is Optimized Link State Routing Protocol (OLSR). As for OLSR research, most research work focus on reducing control traffic overhead and choosing relay point. In addition, because OLSR is mostly dependent on link detection and propagation, dynamic Hello timer become research challenges. However, different timer interval causes imbalance of link validity time by affecting link lifetime. To solve this problem, we propose a weighted topology graph model for constructing a robust network topology based on the link validity time. In order to calculate the link validity time, we use control message timer, which is set for each node. The simulation results show that the proposed mechanism is able to achieve high end-to-end reliability and low end-to-end delay in small networks.

• 전자공학회논문지
• /
• 제54권5호
• /
• pp.109-119
• /
• 2017

본 논문에서는 기존의 보행 분석의 제한점을 개선한 보행분석 방법으로 보행불균형을 판단하기 위해 자체 제작한 좌 우측 고관절, 슬관절의 각도 측정 장비 및 SI 지표를 활용한 판단 시스템과 개인별 보행 상태의 양상을 분석하기 위해 DTW 유사도 분석 알고리즘을 이용한 보행 분석 방법을 제한한다. 실험은 보행 장애가 없는 총 12명의 피험자를 대상으로 정상 보행 및 불균형 보행 실험을 진행하였다. 실험결과 좌 우측 고관절과 슬관절의 각도 측정을 통한 불균형 판단 SI 지수 산출을 통해 정상 보행과 불균형 보행 모두 판단을 할 수 있었다. 개인별 보행특성 분석에서는 실험에 참여한 12명의 피험자를 대상으로 정상보행과 불균형 보행 시 허리 중앙, 좌 우측 허벅지, 발등의 측정 부위에 대한 유사도를 각각 비교하였다. 피험자별 정상 보행 및 불균형 보행 시 측정한 값에 대한 유사도 분석을 통해 보행 동작을 수행하는 동안 항시 같은 패턴의 보행 동작을 유지하는 것이 아니라는 점을 분석 결과 판단할 수 있었다.

• 대한정형도수물리치료학회지
• /
• 제29권3호
• /
• pp.43-53
• /
• 2023

Background: Patients with neck pain develop instability due to muscle imbalance, decreased proprioception, and balance disorders. Studies have examined various exercise methods as treatment methods, but few studies have compared the effects of cervical stabilization exercise and dynamic balance exercise. The purpose of this study was to investigate the effects of dynamic balance exercise on pain, functional level, and psychosocial level in patients with non-specific chronic neck pain. Methods: Thirty-four non-specific chronic neck pain patients were randomly assigned to the experimental group (EG, n=17) and control group (CG, n=17); the cervical stabilization exercise and dynamic balance exercise program were applied to the EG; and only the cervical stabilization exercise program was applied to the CG. The intervention was conducted twice a week, for six weeks. Assessment items evaluated pain, dysfunction (Korean version neck disability index), range of motion, craniocervical flexion test, cervical deep flexor endurance test, and psychosocial level. Data analysis was performed using intention-to-treat analysis as assigned. To analyze differences in the items assessed in the two groups, we used a repeated measures analysis of variance with an interaction between group (EG, CG) and time point (baseline, 6 weeks, 12 weeks). Results: The endurance of the cervical flexor muscles between the group and the measurement point after intervention (p<.05). Both groups showed significantly improved endurance between time points after the intervention (p<.05), with the EG showing a greater change than the CG. None of the other measurement items differed in the pattern of change between measurement points. Conclusion: In conclusion, the EG applying a cervical stabilization exercise and a dynamic balance exercise experienced a significant difference in muscle endurance improvement compared to the CG. We propose an exercise intervention program that includes stabilization exercises and dynamic balance exercises for patients with chronic cervical pain who lack muscle endurance.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
• /
• pp.192-193
• /
• 2006

An AC electrical railroad system has rapidly changing dynamic single-phase load, and at a feeding substation, three-phase electric power is transformed to the paired directional single-phase electric power. There is a great difference in electrical phenomenon between the load of AC electrical railroad system and that of general power system. Electric characteristics of AC electrical railroad's trainload are changed continuously according to the traction, operating characteristic, operating schedule, track slope, etc. Because of the long feeding distance of the dynamic trainload, power quality problems such as voltage drop, voltage imbalance and harmonic distortion may also occur to AC electrical railroad system. These problems affect not only power system stability. but also power quality deterioration in AC electrical railroad system. The dynamic simulation model of AC electrical railroad system presented by PSCAD/EMTDC is modeled in this paper, and then, it is analyzed voltage drop and power quality for AC electrical railroad system both with single-Phase distributed STATCOM(Static Synchronous Compensator) installed at SP(Sectioning Post) and without.

• 무역학회지
• /
• 제47권3호
• /
• pp.141-156
• /
• 2022

This study intends to examine the regional blocs of the international crude oil futures market by analyzing the dynamic conditional correlation between the international crude oil futures markets using the DCC-GARCH model. For statistical data, from April 2, 2018 to March 31, 2022, international crude oil futures prices such as Europe, the United States, China, and Dubai were used. To summarize the results of the study, first, the phenomenon of regional blocs in the international crude oil futures market is occurring, and it is found that it is gradually strengthening as time goes by. Second, it was found that the dynamic correlation of the international crude oil futures market is temporarily strengthened when a supply-demand imbalance problem occurs due to a global shock. Third, it was found that the volatility of the Chinese crude oil futures market affects the international crude oil futures market. This study confirmed that the regional blocs phenomenon in the international crude oil futures market is strengthened as time goes by. In particular, it suggested that China's influence in the international oil market would increase.

• The Journal of Korean Physical Therapy
• /
• 제26권1호
• /
• pp.21-26
• /
• 2014

Purpose: This study examined the effect of trunk stabilization exercise upon the lumbar stabilization and foot pressure on an unstable surface with back pain. Methods: The subjects of the study were 10 patients who showed the symptom of back pain with excessive lumbar curve. This study was 4 weeks, 30 minutes per session, three times a week for a total of 12 times as a result of exercise radiation imaging device and foot pressure analyzer. Results: The sacrohorizontal angle was statistically significant(p<0.05). Comparison of the difference between static right and left foot pressure ratio analysis was statistically significant(p<0.05). Dynamic right and left foot pressure comparisons for the difference was statistically significant in the analysis (p<0.05). Conclusion: Trunk stabilization exercise and the reduction of the excessive sacrohorizontal angle, and static and dynamic foot pressure imbalance reduced left and right.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제10권9호
• /
• pp.4207-4222
• /
• 2016

In a P2P (Peer-to-Peer) VoD (video-on-Demand) streaming system, the nodes' load is an important factor which affects the system performance. In the system, some nodes may receive too many requests, which leads to overload. On the other hand, some other nodes may receive too few requests, which leads to low utilization. Therefore, designing a reasonable load balancing strategy is important. However, existing related studies cannot handle this problem effectively, because they don't have an efficient dynamic load information management mechanism, and they don't distinguish the difference of requests when transfer the nodes' load. In this paper, to manage the dynamic load information efficiently, we design a load management table for each node. Based on the load information, we propose a load balancing strategy which uses a request migration algorithm (LBRM). Through simulations, our scheme can handle the load imbalance problem effectively and improve the users' playback fluency.

• 한국멀티미디어학회논문지
• /
• 제2권1호
• /
• pp.22-29
• /
• 1999

주문형 비디오 시스템에서 영화는 다중 엑세스를 지원하기 위하여 비디오 서버의 디스크 배열에 스트라이프 된다. 영화의 블록들은 비디오 서버의 디스크 배열들간의 부하 불균형을 피할 뿐만 아니라 저장 공간과 장치 대역폭을 최대로 이용하기 위하여 비디오 서버의 디스크 배열에 신중히 배치되어야 한다. 본 논문에서는 영화의 인기도를 고려한 동적 디스크 스트라이핑에 기초한 그룹교대 라운드로빈(GARR: group-alternation round-robin)이라 부르는 영화 배치 방법을 제안한다. GARR은 영화 선택 정책으로 그룹교대와 영화 배치정책으로 라운드로빈을 사용한다. 여기서 그룹교대는 인기 영화 그룹과 비인기 영화의 그룹을 교대로 디스크에 할당한다. GARR의 성능은 시뮬레이션을 통하여 평가된다.

• ETRI Journal
• /
• 제33권6호
• /
• pp.857-863
• /
• 2011

Due to uncertainties in target motion and randomness of deployed sensor nodes, the problem of imbalance of energy consumption arises from sensor scheduling. This paper presents an energy-efficient adaptive sensor scheduling for a target monitoring algorithm in a local monitoring region of wireless sensor networks. Owing to excessive scheduling of an individual node, one node with a high value generated by a decision function is preferentially selected as a tasking node to balance the local energy consumption of a dynamic clustering, and the node with the highest value is chosen as the cluster head. Others with lower ones are in reserve. In addition, an optimization problem is derived to satisfy the problem of sensor scheduling subject to the joint detection probability for tasking sensors. Particles of the target in particle filter algorithm are resampled for a higher tracking accuracy. Simulation results show this algorithm can improve the required tracking accuracy, and nodes are efficiently scheduled. Hence, there is a 41.67% savings in energy consumption.

• 한국항공우주학회지
• /
• 제38권12호
• /
• pp.1162-1169
• /
• 2010

블레이드 제작 공정 및 환경적인 요인에 의해 로터 시스템에는 다양한 불균형 특성이 존재하며 이를 해소하기 위해서는 동적 밸런싱 과정이 요구된다. 본 연구에서는 훨타워 시험으로부터 얻은 블레이드 트랙 결과를 토대로 헬리콥터 로터 시스템 동적 밸런싱의 지표가 되는 시험 D/B의 누적 모듈과 이를 바탕으로 최적의 조절 파라미터 이동량을 산출 할 수 있는 통합 해석 시스템 구축에 대해 고찰하였다. 해석의 간단을 기하기 위해 밸런싱 입력변수의 조절에 대한 블레이드의 응답 특성을 선형으로 가정하고 블레이드 간의 상호 영향성 계수를 도출하였으며, 이로부터 로터 시스템의 특성을 식별하였다. 아울러 유전자 알고리즘을 도입하여 동적 밸런싱을 위한 최적의 블레이드 개별 조절 값을 구하고 이를 시험결과와 비교하였으며, 제시한 방법이 매우 효율적임을 보였다.