모바일 통신 환경을 위한 자료동기화 서버 설계

박주건(Ju-Geon Pak),박기현(Kee-Hyun Park),우종정(Jongjung Woo) 한국정보기술학회 2010 한국정보기술학회논문지 Vol.8 No.2

Data synchronization techniques are required to keep shared data up-to-date and consistent under mobile communication environments. In addition to the smooth execution of data synchronization processes for data synchronization clients, a data synchronization server should select the optimal synchronization type, track all changes, detect data conflicts and resolve all conflicts. The purpose of this paper is to design a data synchronization server to meet requirements derived from the existing synchronization protocols and solutions. In addition, for interoperability with other mobile devices, it is designed to support the OMA DS protocol, one of world-wide standard data synchronization protocols. It consists of a Protocol Manager module, a Synchronization Manager module, a Database Manager module and a database. The Protocol Manager module performs preprocessing for synchronization and the Synchronization Manager module determines policies and types of synchronization. The Database Manager module and a database extract and store data/information for synchronization.

그룹 몰입도 판단을 위한 움직임 동기화 연구

류준모(Joon Mo, Ryu),박승보(Seung-Bo, Park),김재경(Jae Kyeong, Kim) 한국지능정보시스템학회 2013 지능정보연구 Vol.19 No.1

Recently, the high value added business is steadily growing in the culture and art area. To generated high value from a performance, the satisfaction of audience is necessary. The flow in a critical factor for satisfaction, and it should be induced from audience and measures. To evaluate interest and emotion of audience on contents, producers or investors need a kind of index for the measurement of the flow. But it is neither easy to define the flow quantitatively, nor to collect audience’s reaction immediately. The previous studies of the group flow were evaluated by the sum of the average value of each person’s reaction. The flow or “good feeling” from each audience was extracted from his face, especially, the change of his (or her) expression and body movement. But it was not easy to handle the large amount of real-time data from each sensor signals. And also it was difficult to set experimental devices, in terms of economic and environmental problems. Because, all participants should have their own personal sensor to check their physical signal. Also each camera should be located in front of their head to catch their looks. Therefore we need more simple system to analyze group flow. This study provides the method for measurement of audiences flow with group synchronization at same time and place. To measure the synchronization, we made real-time processing system using the Differential Image and Group Emotion Analysis (GEA) system. Differential Image was obtained from camera and by the previous frame was subtracted from present frame. So the movement variation on audience’s reaction was obtained. And then we developed a program, GEX(Group Emotion Analysis), for flow judgment model. After the measurement of the audience’s reaction, the synchronization is divided as Dynamic State Synchronization and Static State Synchronization. The Dynamic State Synchronization accompanies audience’s active reaction, while the Static State Synchronization means to movement of audience. The Dynamic State Synchronization can be caused by the audience’s surprise action such as scary, creepy or reversal scene. And the Static State Synchronization was triggered by impressed or sad scene. Therefore we showed them several short movies containing various scenes mentioned previously. And these kind of scenes made them sad, clap, and creepy, etc. To check the movement of audience, we defined the critical point, αand β. Dynamic State Synchronization was meaningful when the movement value was over critical point β, while Static State Synchronization was effective under critical point α. β is made by audience’clapping movement of 10 teams in stead of using average number of movement. After checking the reactive movement of audience, the percentage(%) ratio was calculated from the division of “people having reaction” by “total people”. Total 37 teams were made in “2012 Seoul DMC Culture Open” and they involved the experiments. First, they followed induction to clap by staff. Second, basic scene for neutralize emotion of audience. Third, flow scene was displayed to audience. Forth, the reversal scene was introduced. And then 24 teams of them were provided with amuse and creepy scenes. And the other 10 teams were exposed with the sad scene. There were clapping and laughing action of audience on the amuse scene with shaking their head or hid with closing eyes. And also the sad or touching scene made them silent. If the results were over about 80%, the group could be judged as the synchronization and the flow were achieved. As a result, the audience showed similar reactions about similar stimulation at same time and place. Once we get an additional normalization and experiment, we can obtain find the flow factor through the synchronization on a much bigger group and this should be useful for planning contents.

Research on the Data Synchronization of Cloud Stroke based on JSON

Hua Gu,LeiHuang,Jing Liu,Qiuli Qin 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.7

Cloud stroke is the cloud platform according to the medical association theory and combing cloud computing technology, build for the hospital systems which are involved in the medical association to sharing and exchange medical information. However, at this stage, there are some problems in the data exchange of the cloud platform: Firstly, every hospital in the medical association needs to configure a front machine and the front machine needs to connect with the cloud platform database directly. So there is a hidden risk for the cloud stroke. Secondly, the data synchronization vector is Excel file, the data reading efficiency is not very well, and at the same time, the front machine memory consumption is relatively very large. This paper, improve the data interactive process of cloud stroke, so that the front machine unneeded to connect with the cloud platform database directly. Then, design data specification and synchronization process based on JSON for cloud stoke information synchronization to compress the expenses, improve the speed and analysis the security of data synchronization.

Low Latency Synchronization Scheme Using Prediction and Avoidance of Synchronization Failure in Heterochronous Clock Domains

Song, Sung-Gun,Park, Seong-Mo,Lee, Jeong-Gun,Oh, Myeong-Hoon The Institute of Electronics and Information Engin 2015 Journal of semiconductor technology and science Vol.15 No.2

For the performance-efficient integration of IPs on an SoC utilizing heterochronous multi-clock domains, we propose a synchronization scheme that causes low latency overhead when data are crossing clock boundaries. The proposed synchronization scheme is composed of a clock predictor and a synchronizer. The clock predictor of a sender clock domain produces a predicted clock that is used in a receiver clock domain to detect possible synchronization failures in advance. When the possible synchronization failures are detected, a synchronizer at the receiver delays data-capture times to avoid the possible synchronization failures. From the simulation of the proposed scheme through SPICE modeling using a Chartered $0.18{\mu}m$ CMOS process, we verified the functionalities and timing behavior of the clock predictor and the synchronizer. The simulation results show that the clock predictor produces a predicted clock before a synchronization failure, and the synchronizer samples data correctly using the predicted clock.

Low Latency Synchronization Scheme Using Prediction and Avoidance of Synchronization Failure in Heterochronous Clock Domains

Sung-Gun Song,Seong-Mo Park,Jeong-Gun Lee,Myeong-Hoon Oh 대한전자공학회 2015 Journal of semiconductor technology and science Vol.15 No.2

For the performance-efficient integration of IPs on an SoC utilizing heterochronous multi-clock domains, we propose a synchronization scheme that causes low latency overhead when data are crossing clock boundaries. The proposed synchronization scheme is composed of a clock predictor and a synchronizer. The clock predictor of a sender clock domain produces a predicted clock that is used in a receiver clock domain to detect possible synchronization failures in advance. When the possible synchronization failures are detected, a synchronizer at the receiver delays data-capture times to avoid the possible synchronization failures. From the simulation of the proposed scheme through SPICE modeling using a Chartered 0.18 mm CMOS process, we verified the functionalities and timing behavior of the clock predictor and the synchronizer. The simulation results show that the clock predictor produces a predicted clock before a synchronization failure, and the synchronizer samples data correctly using the predicted clock.

Implementation and Evaluation of a Time Synchronization Protocol for USN

양도(Tao Yang),이형봉(Hyung-Bong Lee) 한국컴퓨터정보학회 2008 韓國컴퓨터情報學會論文誌 Vol.13 No.7

다수의 독립적인 시스템들이 네트워크를 통해 구성하는 분산 처리 환경에서 시간에 대한 일치성을 유지하는 일은 매우 중요하면서도 어렵다. 특히, 에너지가 제한되어 있고, 통신 기능이 연약한 USN 환경에서의 시간 동기화는 더욱 어렵다. 이러한 어려움에도 불구하고, USN에서 요구되는 시간 동기화 정밀도는 인터넷과 같은 일반적인 분산 처리 환경에서보다 더 높다. USN에서 매우 엄격한 시간 동기화를 요구하는 전형적인 응용 영역으로 TDMA MAC을 들 수 있다. 이 논문에서는 USN을 위해 최근에 제안된 FTSP (Flooding Time Synchronization Protocol) 시간 동기화 알고리즘을 개선한 새로운 알고리즘 FTSF(Flooding Time Synchronization Protocol)을 제안하고 평가한다. HTSP의 시간 동기화 정밀도는 FTSP와 동일하지만, 동기화를 위한 방송메시지 수를 줄임으로써 에너지 소모를 FTSP 보다 절약한다. 평가를 위한 시뮬레이션 결과, FTSP 대비 HTSP의 에너지 절약 비율이 약 26% 정도로 나타났다. In a distributed processing environment composed of many independent systems connected by networks, it is very important and difficult to make time synchronization between the systems. Especially in the USN environment the time synchronization is still more difficult than in general distributed processing environment because energy is limited and communication function is feeble. Even though of these difficulties, the USN environment requires higher precision of time synchronization. We of the typical applications requesting very strict time synchronization in USN is TDMA MAC. This paper proposes and evaluates a new time synchronization protocol HTSP(Hierarchical Time Synchronization Protocol) which is an advanced version of the FTSP(Flooding Time Synchronization Protocol) published recently. The time synchronization precision of the HTSP is equal to that of the FTSP, but the energy consumption of the HTSP is lower than that of the FTSP owing to the reduced number of broadcast messages. The simulation results show that the energy consumption of the HTSP is only 74% of that of the FTSP.

An Efficient Approach for Inter-Process Synchronization Problem

B. Srinuvasu Kumar,K. Kondaiah,L. Rohit,K. V. Sowmya,N. Sri Prakash 보안공학연구지원센터 2014 International Journal of Software Engineering and Vol.8 No.12

For efficient utilization of CPU and speed up the process done by CPU inter-process synchronization became most important feature in operating system. But no operating system will directly provide support for Inter-Process Synchronization. Inter-Process Synchronization means two or more processes accessing a shared resource and performing some operation at the same time, it also provides concurrent computing among processes. In such instance, data inconsistency may occur because of updating the same shared data item by two processes at the same time. This is the standard problem which occur in any operating system. To avoid such problems some of the synchronization primitives need to be followed. Many solutions have been provided to solve the standard problem such as Blocking Mechanisms, Non-Blocking Mechanisms etc. But those mechanisms are not able to provide an optimal solution. Our idea is to develop an agent which will run in background and automatically detects Inter Process Synchronization problem and solve it without any human intervention. In this paper we are going to provide an agent based solution and develop algorithms for that which ensures smoothly execution of multiple processes without any synchronization problems and increase the performance of the CPU.

3GPP LTE 하향링크 OFDMA 시스템의 수신 성능 향상을 위한 주파수 동기 알고리즘

이대홍(Dae-Hong Lee),임세빈(Se-Bin Im),노희진(Hee-Jin Roh),최형진(Hyung-Jin Choi) 한국통신학회 2009 韓國通信學會論文誌 Vol.34 No.1C

본 논문에서는 3GPP LTE(Long Term Evolution)에서 하향링크로 고려하고 있는 OFDMA (Orthogonal Frequency Division Multiple Access) 시스템의 주파수 동기를 위한 수신기 구조를 제안한다. 일반적으로 OFDMA 시스템에서는 대략적 주파수 동기와 미세 주파수 동기가 구분되어 수행된다. 본 논문에서는 대략적 주파수 동기를 위해 동기 채널인 P-SCH(Primary-Synchronization Channel) 신호를 사용하고, 미세 주파수 동기를 위해서는 OFDMA 심볼의 보호구간(CP: Cyclic Prefix)을 이용하는 방안을 고려한다. P-SCH 신호는 이용 가능한 부반송파 개수가 충분히 많지 않고, ZC(Zadoff Chu) 시퀀스 특유의 성질로 인해 차동 상관 특성이 비교적 좋지 않은 단점이 있다. 따라서 기존 대략적 주파수 동기 알고리즘들은 충분한 성능 이득을 얻지 못한다. 본 논문에서는 대략적 주파수 동기 성능 향상을 위해 기존 차동 상관 알고리즘을 변형한 새로운 방식을 제안한다. 또한, 미세주파수 동기의 안정된 성능을 보장하기 위해 효과적인 PLL(Phase Locked Loop) 구조를 제시한다. 컴퓨터 모의실험 결과를 통해 본 논문에서 제안한 대략적 주파수 동기 알고리즘은 기존 방식들에 비해 상대적으로 우수한 성능을 발휘하며, 2차 PLL을 통한 미세 주파수 옵셋 추적 방식은 고속 이동체 환경에서도 충분히 우수한 성능을 나타낸다는 것을 확인할 수 있다. In this paper, we propose a receiver structure for frequency synchronization in OFDMA (Orthogonal Frequency Division Multiple Access) system which is considered as 3GPP LTE(Long Term Evolution) downlink. In general, OFDMA frequency synchronization consists of two parts: coarse synchronization and fine synchronization. We consider P-SCH (Primary-Synchronization Channel) and CP (Cyclic Prefix) of OFDMA symbol for coarse synchronization and fine synchronization, respectively. The P-SCH signal has two remarkable disadvantages that it does not have sufficiently many sub-carriers and its differential correlation characteristic is not good due to ZC (Zadoff Chu) sequence-specific property. Hence, conventional frequency synchronization algorithms cannot obtain satisfactory performance gain. In this paper, we propose a modified differential correlation algorithm to improve performance of the coarse frequency synchronization. Also, we introduce an effective PLL (Phase Locked Loop) structure to guarantee stable performance of the fine frequency synchronization. Simulation results verify that the proposed algorithm has superior performance to the conventional algorithms and the 2nd-order PLL is effective to track the fine frequency offset even in high mobility.

An Algorithm for Inter-Satellite Autonomous Time Synchronization and Ranging in the Beidou Navigation Satellite System

Pan Yi,Liu Huafu,Zhang Zhuxian,Huang Feijiang,Cai Chenglin,Feng Lu 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.7

Aiming at the requirement of the autonomous time synchronization in BeiDou Navigation Satellite System (BDS), an algorithm for inter-satellite autonomous time synchronization and ranging is proposed. Based on the establishment of the inter-satellite link length model of the BDS, a series of simulation has been carried out through the use of STK (Satellite Tool Kit), which includes the simulation of the length changing rules, the length variation scale and its variation ratio. Based on these simulations, an analysis of the impact of satellite motion on the inter-satellite two-way time synchronization and range has been presented. In this algorithm, the inter-satellite clock-offset and range with minimal error are acquired by utilizing the combination of clock-offset fitting polynomial and range fitting polynomial based on the least square fitting of data generated from the inter-satellite two-way time synchronization. Empirical evaluation of the BDS simulation shows that our time synchronization error is 2ns, and ranging error is 2m under the condition of acceptable simulation error. With the application of the algorithm to the inter-satellite autonomous time synchronization and ranging, the high-accuracy measurement of inter-satellite clock-offset and range of BDS can be reached.

혼합형 다중스레드 구조에서의 빠른 동기화에 관한 연구

김정환 建國大學校 自然科學硏究所 2001 建國自然科學硏究誌 Vol.12 No.-

This paper proposes a fast synchronization mechanism for dataflow / von Neumann hybrid multithreaded architecture. Especially, this work has been done over DAVRID (DAtaflow Von neumann Risc hybrID) which developed for massively parallel processing. DAVRID is based on the hybrid computational model. The original architecture of DAVRID uses frame-based synchronization, in which synchronization is performed on a frame memory. In fast synchronization, the information of synchronization locates at a special synchronization memory, instead of a frame memory. The fast synchronization is advantageous in two points: memory conflicts can be reduced and it is possible to exploit locality during synchronization. Simulation result shows the fast synchronization reduces the memory conflicts and improves performance.