• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.9 no.1
• /
• pp.34-49
• /
• 2015

Market means of spectrum trading have been utilized as a vital method of spectrum sharing and access in future cognitive radio system. In this paper, we consider the spectrum trading with multiple primary carrier providers (PCP) leasing the spectrum to multiple secondary carrier providers (SCP) for a short period of time. Several factors including the price of the resource, duration of leasing, and the spectrum quality guides the proposed model. We formulate three trading policies based on the game theory for dynamic spectrum access in a LTE based cognitive radio system (CRS). In the first, we consider utility function based resource sharing (UFRS) without any knowledge of past transaction. In the second policy, each SCP deals with PCP using a non-cooperative resource sharing (NCRS) method which employs optimal strategy based on reinforcement learning. In variation of second policy, third policy adopts a Nash bargaining while incorporating a recommendation entity in resource sharing (RERS). The simulation results suggest overall increase in throughput while maintaining higher spectrum efficiency and fairness.

• Journal of Korea Game Society
• /
• v.7 no.3
• /
• pp.31-38
• /
• 2007

In this paper, we proposed an effective visibility test architecture with improving the mid-texturing architecture. The proposed architecture uses the property of fragments that the visibility of adjacent fragments is identical, and performs only a single visibility test per fragment. To compare with the mid-texturing architecture, simulation results show that the bandwidth requirements and the cell area of the depth cache in the proposed architecture are reduce by 25% and 34%, respectively, in exchange for less than 5% performance decline.

• Journal of Korea Game Society
• /
• v.8 no.3
• /
• pp.69-76
• /
• 2008

This paper presents a novel rendering algorithm based on sperical coordinate representation of the object. The vertices of the object are transformed into the sperical coordinate system, and we construct additional maps: the centroid and index of the triangle, the memory access table. While OpenGL rendering pipeline touches all vertices of an object, the proposed method takes account of the only visible vertices by examining the visible triangles of the object. Simulation results demonstrated that the proposed method achieve an efficient rendering performace.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.10 no.11
• /
• pp.5322-5342
• /
• 2016

In vehicle-to-vehicle (V2V) networks, where selfishness degrades node activity, countermeasures for collaboration enforcement must be provided to enable application of a sage and efficient network environment. Because vehicular networks feature both high mobility and various topologies, selfish behavior judgment and establishment of a stable routing protocol become intensely challenging. In this paper, a two-phase-based generous cooperative routing protocol (called GEC) is presented for V2V networks to provide resistance to selfishness. To detect selfish behaving vehicles, a packet forwarding watchdog and an average connection rate based on the multipath weight method are used, where evidence is gathered from different watchdogs. Then, multihop relay decisions are made using a generous cooperative algorithm based on game theory. Finally, through buffering of the multiple end-to-end paths and judicious choice of optimal cooperative routes, route maintenance phase is capable of dealing with congestion and rapidly exchanging traffic. Specifically, it is proved that the GEC is theoretically subgame perfect. Simulation results show that for V2V networks with inherently selfish nodes, the proposed method isolates uncooperative vehicles and is capable of accommodating both the mobility and congestion circumstances by facilitating information dissemination and reducing end-to-end delay.

• Journal of Korea Game Society
• /
• v.10 no.1
• /
• pp.157-165
• /
• 2010

This paper presents a novel real-time rendering algorithm based on spherical coordinate system of the object using convex hull. While OpenGL rendering pipeline touches all vertices of an object, the proposed method takes account the only visible vertices by examining the visible triangles of the object. In order to determine the visible areas of the object in its spherical coordinate representation, the proposed method uses 3D geometric relation of 6 plane equations of the camera frustum and the bounding sphere of the object. In addition, we compute the convex hull of the object and its maximum side factors for hidden surface removal. Simulation results showed that the quality of result image is almost same compared to original image and rendering performance is greatly improved.

• Environmental and Resource Economics Review
• /
• v.14 no.3
• /
• pp.753-773
• /
• 2005

This paper is a study of the investment dynamics focusing on crude oil supply by OPEC and non-OPEC. Oil supply capacity is first determined by a leader, OPEC, and by an aggregate that represents non-OPEC producers. OPEC wants to increase a gain from oil price increase while keeping its market share relative to non-OPEC's share. An investment rule model is developed for OPEC crude oil supply capacity in response to non-OPEC's decision. In presence of oil price uncertainty, oil price threshold is derived above which it is optimal for OPEC to expand oil supply capacity since otherwise the increased supply of non-OPEC results in weakening of OPEC market share in the world oil market. In addition, a lower threshold price is derived below which OPEC triggers a capacity reduction to regain its otherwise forgone profits. A simulation is provided for calculating the capacity expansion and reduction thresholds.

• Journal of the Ergonomics Society of Korea
• /
• v.31 no.4
• /
• pp.577-583
• /
• 2012

Objective: This paper describes the process and results related to the development of gesture recognition-based natural user interface(NUI) for vehicle maintenance e-Training system. Background: E-Training refers to education training that acquires and improves the necessary capabilities to perform tasks by using information and communication technology(simulation, 3D virtual reality, and augmented reality), device(PC, tablet, smartphone, and HMD), and environment(wired/wireless internet and cloud computing). Method: Palm movement from depth camera is used as a pointing device, where finger movement is extracted by using OpenCV library as a selection protocol. Results: The proposed NUI allows trainees to control objects, such as cars and engines, on a large screen through gesture recognition. In addition, it includes the learning environment to understand the procedure of either assemble or disassemble certain parts. Conclusion: Future works are related to the implementation of gesture recognition technology for a multiple number of trainees. Application: The results of this interface can be applied not only in e-Training system, but also in other systems, such as digital signage, tangible game, controlling 3D contents, etc.

• Journal of Korea Game Society
• /
• v.13 no.1
• /
• pp.41-48
• /
• 2013

In general, the predator-prey model has been studied as a model of struggle for existence in a ecosystem. While conventional papers have focussed on the population change of the predator-prey, this paper focused on controlling the energy needed for the predator to pursue the prey. For simplification, assume the environment which there are only single predator and prey. Based on the environment, a certain amount of energy needed for a predator to pursue the prey was suggested on a basis of physical theories and also the used energy model was suggested on a basis of the simulation. From experiments, it was proven that the suggested energy models were appropriate for natural pursuit.

• Journal of Korea Game Society
• /
• v.20 no.3
• /
• pp.25-34
• /
• 2020

This study is a VR system design designed to evaluate the impact of interaction on user experience analyzed by developer's perspective for the interactive VR fashion show. In the VR fashion show design, we produced an interactive system through the four interactive elements of camera viewpoint, cloth, effects, and sound. The interactive design system is proposed based on three application facto rs in VR space design: speed, range, and mapping. The study focused on the user experience based on format conversion to apply the Unity3D engine using 3D model, animation, 2D UI design, and simulation.

• Journal of Korea Game Society
• /
• v.20 no.3
• /
• pp.85-94
• /
• 2020

AI-based smart factory technologies are only increase short-term productivity. To solve this problem, collaborative intelligence combines human teamwork, creativity, AI speed, and accuracy to actively compensate for each other's shortcomings. However, current automation equipmens require high safety measures due to the high disaster intensity in the event of an accident. In this paper, we design and implement a factory safety control system that uses a depth camera to implement workers and facilities in the virtual world and to determine the safety of workers through simulation.