• Korean Journal of Biological Psychiatry
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• v.24 no.2
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• pp.52-58
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• 2017

Due to the increasing use of the internet, various social problems have been emerging, and one of them is internet gaming disorder (IGD). The purpose of this study was to investigate whether low internal motivation was present in IGD and basic psychological needs affected internal motivation. Twenty-one individuals with IGD and 21 healthy controls performed a 'motivation task' in which the avatar in virtual reality asked whether they would accept an activity in two conditions stimulating intrinsic or extrinsic motivation. The task performance was compared between the two groups, and was correlated with the Basic Psychological Needs Scale scores. Patients had a significantly lower acceptance rate of the proposal in the intrinsic motivation condition than controls, and this intrinsic motivated tendency was correlated with the satisfaction in their basic psychological needs. As with other substance use disorders, IGD was associated with a lower level of internal motivation, which was related to the dissatisfaction of basic psychological needs such as autonomy, competence, and relationship.

• Proceedings of the Korean Society for Cognitive Science Conference
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• 2010.05a
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• pp.37-41
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• 2010

The previous investigations of electroencephalogram (EEG) activity in the memory retrieval tasks demonstrated that event-related potentials (ERP) during recollection showed different durations and the peak levels from those without recollection. However, it has been unknown that recollection in memory retrieval also modulates high-frequency brain rhythms as well as establishes large-scale synchronization across different cortical areas. In this study, we examined the spectral components of the EEG signals, especially the gamma bands (20-80Hz), measured during the memory retrieval tasks. Specifically, we focused on two major spectral components: first, we evaluated the temporal patterns of the power spectral density before and after the onset of the memory retrieval task; second, we estimated phase synchrony between all possible pairs of EEG channels to evaluate large-scale synchronization. Fourteen healthy subjects performed the memory retrieval task in the virtual reality environment where they selected whether or not t he present item was seen in the previous training period. When the subjects viewed the unseen items, the middle gamma power (40-60Hz) appeared to increase 200-500ms after stimulus onset while the low gamma power (20Hz) was suppressed all the way through the post-stimulus period 150ms after onset. The degree of phase synchronization in this low gamma level, however, increased when the subjects fetched the item from memory. This suggests that phase synchrony analysis might reveal different aspects of the memory retrieval process than the gamma power, providing additional information to the inference on the brain dynamics during memory retrieval.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.1
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• pp.39-60
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• 2017

In the Cloud, for the scheduling of parallel jobs, there are many tasks in a job and those tasks are executed concurrently on different VMs (Visual machines), where each task of the job will be executed synchronously. The goal of scheduling is to reduce the execution time and to keep the fairness between jobs to prevent some jobs from waiting more time than others. We propose a Cloud model which has multiple Clouds, and under this model, jobs are in different lists according to the waiting time of the jobs and every job has different parallelism. At the same time, a new method-ZOMT (the scheduling parallel tasks based on ZERO-ONE scheduling with multiple targets) is proposed to solve the problem of scheduling parallel jobs in the Cloud. Simulations of ZOMT, AFCFS (Adapted First Come First Served), LJFS (Largest Job First Served) and Fair are executed to test the performance of those methods. Metrics about the waiting time, and response time are used to test the performance of ZOMT. The simulation results have shown that ZOMT not only reduces waiting time and response time, but also provides fairness to jobs.

• The Journal of Korea Robotics Society
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• v.14 no.3
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• pp.179-185
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• 2019

This paper presents cable-hydraulic driven 3DoF (Degree-of-Freedom) manipulator for cooperative robot with high output/low inertia and enhancing lager workspace of hydraulic manipulator. Hydraulic actuation could be solution to design more higher output manipulator than the one of electric motor actuation due to install actuation source and robot joint separated. In spite of this advantage, the conventional hydraulic driven manipulator using cylinder or vane actuator is not suitable for the candidate of cooperative robot because smaller workspace owing to small RoM (Range of Motion) hydraulic actuator. In this paper, we propose 3DoF manipulator with cable-hydraulic actuation which is more larger ratio of payload-to-weight than the one of conventional cooperative manipulator and larger workspace than the one of existing hydraulic driven manipulator. The performance of proposed manipulator was demonstrated by the experiments for confirming overall workspace task, high payload operation task under worst situation and comparing repeatability between developed manipulator and existed cooperative robots. The results of experiments showed that the appropriate performance of proposed manipulator for cooperative robot.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.622-627
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• 2009

Business process engineering (BPE) is a top-down management approach for increasing efficiency and productivity through radical and fundamental changes to the business processes of the organization. BPE requires firms to initially develop a model of the existing business processes of the firm to distinguish functional tasks from processes used for coordinating inputs, activities and outputs. The model is used for understanding the business processes in the organization and to simulate the effect of changes to the processes. The model can also be used to justify business processes, which involves assessing whether the business process provides value to the customer in its current configuration. Justification requires a careful examination of the key business processes used by the firm to identify systemic shortcomings in the process and to create a new business process to produce greater efficiency. BPE also considers automating as many business processes as possible to increase operational efficiency and the integration of business process tasks. The construction industry has been slow to adopt BPE because of its project approach in which a major firm contracts with various functional service providers and regards each project as unique. The industry focuses on functional task efficiency rather than business process efficiency. There is no formal methodology or criteria for determining whether a business process is effective for a construction firm in its current configuration. The use of performance measures such as costs, task duration times or other metrics can be useful in evaluating the effectiveness of an existing business process and for modeling the possible outcome of a fundamental and radical change to the process.

• Korean Journal of Computational Design and Engineering
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• v.17 no.6
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• pp.417-425
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• 2012

In recent years, great attention has been paid to using simple physical objects as tangible objects to improve user interaction in augmented reality (AR) environments. In this paper, we address AR-based user interaction using tangible objects, which has been used as a key component for virtual design evaluation of engineered products including digital handheld products. We herein consider the use of two types (product-type and pointer-type) of tangible objects. The user creates input events by touching specified parts of the product-type object with the pointer-type object, and the virtual product reacts to the events by rendering its visual and auditory contents on the output devices. The product-type object is used to reflect the geometric shape of a product of interest and to determine its position and orientation in the AR environment. The pointer-type object is used to recognize the reference position of the pointer (or finger) in the same environment. The rapid prototype of the product is employed as a good alternative to the product-type object, but various alternatives to the pointer-type object can be considered according to fabrication process and touching mechanism. In this paper, we present four alternatives to the pointer-type object and investigate their strong and weak points by performing experimental comparison of their various aspects including interaction accuracy, task performance, and qualitative user experience.

• Journal of Broadcast Engineering
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• v.22 no.5
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• pp.600-607
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• 2017

Virtual Reality (VR) has lately gained significant attention primarily driven by the recent market availability of consumer devices, such as mobile phone-based Head Mounted Displays (HMDs). Apart from classic gaming use cases, the delivery of $360^{\circ}$ video is considered as another major application and is expected to be ubiquitous in the near future. However, the delivery and decoding of high-resolution $360^{\circ}$ videos in desirable quality is a challenging task due to network limitations and constraints on available end device decoding and processing. In this paper, we focus on aspects of $360^{\circ}$ video streaming and provide an overview and discussion of possible solutions as well as considerations for future VR video streaming applications. This paper mainly focuses on the status of the standardization activities, Omnidirectional MediA Format (OMAF), to support interoperable $360^{\circ}$ video streaming services. More concretely, MPEG's ongoing work for OMA aims at harmonization of VR video platforms and applications. The paper also discusses the integration in MPEG Dynamic Adaptive Streaming over HTTP (MPEG-DASH), which is considered as $360^{\circ}$ video streaming services with OMAF content. In context of the general OMAF service architecture.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.125-129
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• 2008

Lying has been such a wrong act in human society, but at the same time we are perpetrating lying surprisingly often in the interpersonal situation. Like this, between what we think and what we do about telling lie is pretty different, and these differences are came from ambivalent attitudes stemmed from different sources which is divided into the implicit and the explicit attitude. We find manipulative liars by simulated racing task by using virtual environment. Implicit Association Test was applied to them to see implicit beliefs, and used self-reported questionnaires to identify explicit attitude about lying. As a result they could manipulate the explicit measures but could not maneuver their own implicit attraction to lie Liars' deceptive behaviors usually occur in subtle and covert way so that it has been hard to notice and to know what lead them to lie. However, as we know those spontaneous process is linked with deception, triggering them lie, it became no more veiled, unpredictable actions.

• The Journal of the Korea Contents Association
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• v.17 no.3
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• pp.222-230
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• 2017

The Ministry of Public Safety and Security plans to expand fire safety education infrastructure to provide customized fire safety education, spread fire safety culture and develop a tailored fire safety education system as a part of the 2016 Citizens' Safety Improvement Policy. This study has also been designed to improve safety problems in the Republic of Korea. Even though safety education has been given, citizens aren't still able to experience a close-to-real situation. In addition, their understanding and satisfaction with the curriculum are very low. Therefore, this study offers VR fire-extinguishing experience education contents as an effective alternative. With a goal of having the participants experience fire extinguishing and evacuation drill in a virtual space, this program has the following advantages: i) safe fire-extinguishing experience; ii) UI to create fun ; iii) useful in fire-extinguishing education; iv) budget saving. we configure the VR fire experience system structure and hardware by applying UX design methodology. We also develop for VR-specific motion recognition plug-in and controller that can be feeling in HMD environment.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.1
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• pp.22-30
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• 2004

As an information-oriented society comes, many people use PC and depend on database that network server has. However, the online data can be missed when a blackout happens and also a power failure effects on standard of judgment on Power Quality. Thus, it is reason of a trend using interruption-free live-line work when a trouble happens to power system. However, the 83％ among the number of people who receive an electric shock experience when a laborer is doing interruption-free live-line works. In interruption-free method, the education and the training problem has been issued. However, we have a few instructors for that training. Furthermore, the trainees have short training period, just 4 weeks. In this paper, to develope the method that has no restriction of a time and place and reduce the wasteful materials, immersion type virtual reality(or environment) technology is used. The users of a 3D immersion type VR training system can interact with the system by doing same action in the real safe environment. Thus, it can be valuable to apply this training system to a dangerous work like as "Interruption-free live-line work exchanging COS(Cut-Out-Switch)". In this program, the user works with a instruction on the window and speaker and can't work other tasks until each part of the task completed. The workers using this system can use their hands and viewpoint movement as he is in a real environment but the trainee can't use all parts and senses of a real body with the current VR technology. Despite of this weak point, when we consider the trends of improvement in electrical devices and communication technology, we can say that 3D graphic VR application has a high potentiality.