• Journal of KIISE:Computing Practices and Letters
• /
• v.16 no.12
• /
• pp.1249-1253
• /
• 2010

As personal computers have been recently improved in performance, the multi tasking of running several applications at the same time has been generalized. Since only one task space is provided for performing such tasks on Windows operating system, a number of computer users feel inconvenient. In this paper, we propose a 3D Virtual Desktop System which can show a process of switching task spaces in 3D motion using DirectX. The proposed system can provide a computer user with more task spaces and the intuitive UI(User Interlace) such as Compiz of Linux.

• The Journal of the Korea Contents Association
• /
• v.17 no.3
• /
• pp.74-87
• /
• 2017

This paper aims to elicit user-defined hand gestures for the small cylindrical displays with flexible displays which has not emerged as a product yet. For this, we first defined the size and functions of a small cylindrical display, and elicited the tasks for operating its functions. Henceforward we implemented the experiment environment which is similar to real cylindrical display usage environment by developing both of a virtual cylindrical display interface and a physical object for operating the virtual cylindrical display. And we showed the results of each task in the virtual cylindrical display to the participants so they could define the hand gestures which are suitable for each task in their opinion. We selected the representative gestures for each task by choosing the gestures of the largest group in each task, and we also calculated agreement scores for each task. Finally we observed mental model of the participants which was applied for eliciting the gestures, based on analyzing the gestures and interview results from the participants.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.7 no.5
• /
• pp.866-874
• /
• 2006

This paper proposes a new Dynamic Voltage Scaling(DVS) algorithm to achieve low-power scheduling of aperiodic hard real-time tasks. Aperiodic tasks schedulingcannot be applied to the conventional DVS algorithm and result in consuming energy more than periodic tasks because they have no period, non predictable worst case execution time, and release time. In this paper, we defined Virtual Periodic Task Set(VTS) which has constant period and worst case execution time, and released aperiodic tasks are assigned to this VTS. The period and worst case execution time of the virtual task can be obtained by calculating task utilization rate of both periodic and aperiodic tasks. The proposed DVS algorithm scales the frequency of both periodic and aperiodic tasks in VTS. Simulation results show that the energy consumption of the proposed algorithm is reduced by 11% over the conventional DVS algorithm for only periodic task.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.7 no.4
• /
• pp.193-199
• /
• 2012

Virtualization allows multiple commodity operating systems to share on a single physical machine. Resource allocation among virtual machines is a key to determine virtual machine performance. To satisfy time-sensitive task on a domain, hypervisor needs to observe the resource requirements and allocates proper amount of CPU resources in a timely manner. In this paper, we propose a realtime credit scheduler for latency sensitive application on virtual machines. The key idea is to register a time event in the Xen hypervisor. Experiment result shows that the proposed scheme is superior to Credit scheduler.

• IE interfaces
• /
• v.18 no.1
• /
• pp.82-87
• /
• 2005

Most of virtual reality systems ask users to control 3D objects or to navigate 3D world using 3D controllers. To maximize the human performance in the control, the design of virtual reality system and its input and output devices should be optimized. In this study, an experiment was designed to investigate the effects of three resolution factors of a virtual reality system on the human performance. Six subjects conducted the experiment for the factors; two frame rates, three spatial resolutions, and three pictorial contents. The result showed that the greater the spatial resolution was, the higher the human performance was. For the temporal resolution, fixed frame rate at 18 Hz was better than the varied maximized frame rate. For the pictorial contents, the virtual space with orientation cues marked the greatest performance than the other two conditions; the virtual space without any orientation cue and the virtual space like real world. These results could be applied for the design of virtual reality systems.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.12 no.9
• /
• pp.4103-4121
• /
• 2018

Quality of Service (QoS) awareness is recognized as a key point for the success of Internet of Things (IOT).Realizing the full potential of the Internet of Things requires, a real-time task scheduling algorithm must be designed to meet the QoS need. In order to schedule tasks with diverse QoS requirements in cloud environment efficiently, we propose a task scheduling strategy based on dynamic priority and load balancing (DPLB) in this paper. The dynamic priority consisted of task value density and the urgency of the task execution, the priority is increased over time to insure that each task can be implemented in time. The scheduling decision variable is composed of time attractiveness considered earliest completion time (ECT) and load brightness considered load status information which by obtain from each virtual machine by topic-based publish/subscribe mechanism. Then sorting tasks by priority and first schedule the task with highest priority to the virtual machine in feasible VMs group which satisfy the QoS requirements of task with maximal. Finally, after this patch tasks are scheduled over, the task migration manager will start work to reduce the load balancing degree.The experimental results show that, compared with the Min-Min, Max-Min, WRR, GAs, and HBB-LB algorithm, the DPLB is more effective, it reduces the Makespan, balances the load of VMs, augments the success completed ratio of tasks before deadline and raises the profit of cloud service per second.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2008.06a
• /
• pp.487-488
• /
• 2008

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.2
• /
• pp.704-710
• /
• 2017

Our research team is developing a 6-DOF manipulator that is adequate for the narrow workspace of press forming processes. This paper addresses the task sequence optimization methods for the manipulator to minimize the task-finishing time. First, a kinematic model of the manipulator is presented, and the anticipated times for moving among the task locations are computed. Then, a mathematical model of the task sequence optimization problem is presented, followed by a comparison of three meta-heuristic methods to solve the optimization problem: an ant colony system, simulated annealing, and a genetic algorithm. The simulation shows that the genetic algorithm is robust to the parameter settings and has the best performance in both minimizing the task-finishing time and the computing time compared to the other methods. Finally, the algorithms were implemented and validated through a simulation using Mathworks' Matlab and Coppelia Robotics' V-REP (virtual robot experimentation platform).

• Korean Journal of Computational Design and Engineering
• /
• v.21 no.1
• /
• pp.20-30
• /
• 2016

Recently immersive virtual reality (VR) becomes popular due to the advanced development of I/O interfaces and related SWs for effectively constructing VR environments. In particular, natural and intuitive manipulation of 3D virtual objects is still considered as one of the most important user interaction issues. This paper presents a comparative study on the manipulation and interaction of 3D virtual objects using different interfaces and interactions in three VR environments. The comparative study includes both quantitative and qualitative aspects. Three different experimental setups are 1) typical desktop-based VR using mouse and keyboard, 2) hand gesture-supported desktop VR using a Leap Motion sensor, and 3) immersive VR by wearing an HMD with hand gesture interaction using a Leap Motion sensor. In the desktop VR with hand gestures, the Leap Motion sensor is put on the desk. On the other hand, in the immersive VR, the sensor is mounted on the HMD so that the user can manipulate virtual objects in the front of the HMD. For the quantitative analysis, a task completion time and success rate were measured. Experimental tasks require complex 3D transformation such as simultaneous 3D translation and 3D rotation. For the qualitative analysis, various factors relating to user experience such as ease of use, natural interaction, and stressfulness were evaluated. The qualitative and quantitative analyses show that the immersive VR with the natural hand gesture provides more intuitive and natural interactions, supports fast and effective performance on task completion, but causes stressful condition.

• International conference on construction engineering and project management
• /
• 2020.12a
• /
• pp.137-145
• /
• 2020

Providing safety training to construction workers is essential to reduce safety accidents at the construction site. With the prosperity of visualization technologies, Immersive Virtual Reality (IVR) has been adopted for construction safety training by providing interactive learning experiences in a virtual environment. Previous research efforts on IVR-based training have found that the level of fidelity of interaction between real and virtual worlds is one of the important factors contributing to the sense of presence that would affect training performance. Various interactive devices that link activities between real and virtual worlds have been applied in IVR-based training, ranging from existing computer input devices (e.g., keyboard, mouse, joystick, etc.) to specially designed devices such as high-end VR simulators. However, the need for high-fidelity interactive devices may hinder the applicability of IVR-based training as they would be more expensive than IVR headsets. In this regard, this study aims to understand the impact of the level of fidelity of interactive devices in the sense of presence in a virtual environment and the training performance during IVR-based forklift safety training. We conducted a comparative study by recruiting sixty participants, splitting them into two groups, and then providing different interactive devices such as a keyboard for a low fidelity group and a steering wheel and pedals for a high-fidelity group. The results showed that there was no significant difference between the two groups in terms of the sense of presence and task performance. These results indicate that the use of low-fidelity interactive devices would be acceptable for IVR-based safety training as safety training focuses on delivering safety knowledge, and thus would be different from skill transferring training that may need more realistic interaction between real and virtual worlds.