• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2003.09a
• /
• pp.616-619
• /
• 2003

In this paper, we develop an input device equipped with accelerometers and gyroscopes. The installed sensors measure the inertial measurements i.e., accelerations and angular rates produced by the movement of the system when a user is writing on the plane surface or in the three dimensional space. The gyroscope measurement are integrated once to give the attitude of the system and consequently used to remove the gravity included in the acceleration measurements. The compensated accelerations bin doubly integrated to yield the position of the system. Due to the integration processes involved in recovering the users'motions, the accuracy of the position estimation significantly deteriorates with time. Among various error sources of the system incorrect estimation of attitude causes the largest portion of the positioning error since the gravity is not fully cancelled. In order to solve this problem, we propose a Kalman filler-based attitude estimation algorithm which fuses measurement data from accelerometers and gyroscopes by fuzzy logic approach. In addition, the online calibration of the gyroscope biases are performed in parallel with the attitude estimation to give more accurate attitude estimation. The effectiveness and the feasibility of the presented system is demonstrated through computer simulations and actual experiments.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.7
• /
• pp.1161-1168
• /
• 2016

Battery energy storage system(BESS) attract the attention of the power system operators with its fast response to a disturbance in spite of its limited energy capacity. This paper proposes the operating method of BESS for following the Automatic Generation Control(AGC) frequency control which is centrally distributed by a system operator. As BESS needs to just meet the control requirement from the system operator, it should be able to properly manage the state of charge(SOC) of BESS to be available to control signal. For doing these, the proposed method distributes the control requirement to available batteries in proportion to its SOC. In addition, unavailable batteries are controlled to recover the SOC to an appropriate range, and the recovering power is supplied by available batteries meeting the control requirement. Moreover, the proposed method manages the efficiency of power conversion system (PCS) by limiting the number of PCS to be assigned for the low control requirement. Finally, the case studies are carried out to verify the effectiveness of proposed strategy.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.8
• /
• pp.5476-5484
• /
• 2015

The purpose of this study was to verify the clinical usefulness of the virtual reality rehabilitation system which Academic-Industrial cooperation develop through clinical experiment for recovering the functional abilities in stroke. For this purpose, 24 Stroke(hemorrhage13, infarction11)participated in a clinical experiment. They were randomly assigned to the virtual reality rehabilitation system group(n=13) and conventional rehabilitation training(Activities of daily living, cognition training, motor control) group(n=11). All participant were evaluated with three standardized assessment tools(Functional Independent Measure; FIM, Mini-Mental State Examination for Korean; MMSE-K, Self-esteem scale) before and after the planned intervention sessions. All participant were intensively carried out for 8weeks, 3times a week. The results were as follows. The experimental group showed significant improvements for Activities of daily living, basic cognitive abilities and self-esteem related with life satisfaction after the interventions(p<.05). There were no significant differences between two groups for all assessment tool after interventions. Because of this experimental results, the virtual reality rehabilitation system showed the clinical utility for recovering the function in stroke. Further studies are needed to verify the clinical usefulness on the improvement of various functions in brain injury and dementia.

• Journal of Convergence for Information Technology
• /
• v.10 no.5
• /
• pp.23-29
• /
• 2020

These days, digital forensic technologies are being used frequently at crime scenes. There are various electronic devices at the scene of the crime, and digital forensic results of these devices are used as important evidence. In particular, the user's action and the time when the action took place are critical. But there are many limitations for use in real forensics analyses because of the short cycle in which user actions are recorded. This paper proposed an efficient method for recovering deleted user behavior records and applying them to forensics investigations, then the proposed method is compared with previous methods. Although there are difference in recovery result depending on the storage, the results have been identified that the amount of user history data is increased from a minimum of 6% to a maximum of 539% when recovered user behavior was utilized to forensics investigation.

• Therapeutic Science for Rehabilitation
• /
• v.2 no.1
• /
• pp.24-35
• /
• 2013

The Purpose of this study was to determine the clinical effectiveness of mirror therapy for stroke. Moreover, this paper was designed to summarize clarified information of neurological plasticity by mirror therapy to finally define the neurological mechanism. Mirror therapy improves the stroke patients' hand and arm motor function. It also has a positive influence on recovering performance of activities of daily living and relieving pain. However, it is not evident that mirror therapy restores visual neglect. There are various ways of recovering stroke. Fundamentally, all the theories are on a bases of restoration of premotor area. Premotor area which is associated with motor control increases the activation of primary motor area and finally improves patients' motor function. If primary motor area is completely damaged, premotor area and supplementary motor substitute for primary motor area. In summary of literature survey, there are not enough evidence to verify the effectiveness and neurological mechanism of mirror therapy. In future, more researches should be conducted to verify the neurological recovery through mirror therapy. Then, mirror therapy will be acknowledged as a clinically effective treatment.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.2 no.1
• /
• pp.57-65
• /
• 1996

The latest date, No. 1 YouII was grounded and sunk into the sea at MAMHYUNGJEDO ( South brother Island) in Sep. 21. 1995, and M.V. Sea Prince of V.L.C.C also made a big oil poullution accident owing to Typhoon "Paei" at front sea of Yeu Choun on Jul. 25. 1995. The large or small scall scale of oil poullution accident frequently was occurred about 300-350 cases per ine(1) year. The countries advanced in marine relations like as, nited Kingdom and Japan, have perfect system The country of expert education, training and oil recovery equipments in oil poullution accidents. The large quantity oil skimming ship's basic condition need general skimming ship which was high speed and large quantity skimming ability , and hve to store the recovered oil into tanks This oil skimming shop are composit the skimmer whuch move up and down according to the wace movements, storage tank which storage the recovered oil in after side, transfer pump which transformed from flooding tank to separating tank and separating tank which separated the oil mixtures, Also there are cylindrical floated which keep the auto positing, gate which keep the auto positing, gate which protect and guide the recovering oil from sea and balance weight for skimmer balance. Also there are cylindrical floated which keep the auto positing, gate which protect and guide the recovering oil from sea and balance weight for skimmer balance. The important arrangement is twin arm which moved by two hinge and move te skimming unit by wave movement. In gate of inside, made long wear in the gate bellow position, there are also connected the flexible hose for oil mixtures drop. The separating tank composited with multi-divided bulkhead for ffective oil and sea water separating by settling and flotation principle. As use the above natural princile and equipment, we can remove the large quantity oil by developed oil skimming ship.ming ship.

• Journal of Digital Contents Society
• /
• v.6 no.1
• /
• pp.79-83
• /
• 2005

Our Digital Carousel enables user to share media objects through media synchronization mechanism. We implemented the Digital Carousel so that the users participated in collaborative work may refer shared media or error objects as the same view to others. This paper explains the design and implementation of the EC_DXS(Error Control in Digital Carousel System). EC_DCS is a system that is suitable for detecting sharing and recovering software error based on multimedia CSCW(Computer Supportes Cooperated Work). With error sharing system, a group cooperating users can share me. applications. From the perspective of multimedia collaborative environment, an error application becomes another interactive presentation error is shared with participant engaged in a cooperative work.

• Journal of the Korean Society for Precision Engineering
• /
• v.24 no.6
• /
• pp.86-95
• /
• 2007

This paper presents the optimal design of an exhaust system of a vacuum-compatible air bearing using a genetic algorithm. To use the air bearings in vacuum conditions, the differential exhaust method is adopted to minimize the air leakage, which prevents air from leaking into a vacuum chamber by recovering air through several successive seal stages in advance. Therefore, the design of the differential exhaust system is very important because several design parameters such as the number of seals, diameter and length of an exhaust tube, pumping speed and ultimate pressure of a vacuum pump, seal length and gap(bearing clearance) influence on the air leakage, that is, chamber's degree of vacuum. In this paper, we used a genetic algorithm to optimize the design parameters of the exhaust system of a vacuum-compatible air bearing under the several constraint conditions. The results indicate that chamber's degree of vacuum after optimization improved dramatically compared to the initial design, and that the distribution of the spatial design parameters, such as exhaust tube diameter and seal length, was well achieved, and that technical limit of the pumping speed was well determined.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.18 no.9
• /
• pp.738-744
• /
• 2006

In order to utilize the condensation heat of refrigerants in condenser on the absorption chiller system, the solution cooled condenser (SCC) was proposed using the weak solution of absorber as a cooling medium. The increase of COP with the increase of UA of the solution cooled condenser was approximately 0.009 in maximum with single effect one, and is about maximum 0.008 in occasion of double effect one with series flow compared to that without. In the case of heat exchanger, effectiveness is about 0.85, it's increments are 0.008 and 0.0072, respectively. And solution cooled condenser is more effective device in the single effect absorption system than double effect system for the principle of operation. On the other hand, as the solution split ratio increases when the value of UA is fixed, COP is increased and as the solution split ratio increases when the value of UA is fixed, COP is increased. If the flow rate of cooling water or the value of UA is reduced in order to increases the heat recovery of solution cooled condenser, heat recovery of solution cooled condenser is increased a little but COP is decreased as the system pressure is increased.

• The Transactions of the Korea Information Processing Society
• /
• v.7 no.6
• /
• pp.1753-1765
• /
• 2000

As the areas of computer application are expanded, real-time application environments that must process as many transactions as possible within their deadlines, such as a stock transaction systems, ATM switching systems etc, have been increased recently. The reason why the conventional database systems can't process soft real-time applications is the lack of prediction and poor performance on processing transaction's deadline. If transactions want to access data stored at the secondary storage, they can not satisfy requirements of real-time applications because of the disk delay time. This paper designs a main-memory database prototype systems to be suitable to real-time applications and then this system can produce rapid results without disk i/o as all of the information are loaded in main memory database. In thesis proposed the improved techniques with respect to logging, checkpointing, and recovering in our environment. In order to improve the performance of the system, a) the frequency of log analysis and redo processing is reduced by the proposed redo technique at system failure, b) database consistency is maintained by improved fuzzy checkpointing. The performance model is proposed which consists of two parts. The first part evaluates log processing time for recovery and compares with other research activities. The second part examines checkpointing behavior.