• Journal of the Korea Society for Simulation
• /
• v.3 no.1
• /
• pp.17-28
• /
• 1994

A statistical procedure is developed to estimate the relative difference between two parameters each obtained from either true model or approximate model. Double sample procedure is applied to find the additional number of simulation runs satisfying the preassigned absolute precision of the confidence interval. Two types of parameters, mean and standard deviation, are considered as the performance measures and tried to show the validity of the model by examining both queues and inventory systems. In each system it is assumed that there are three distinct means and their own standard deviations and they form the simultaneous confidence intervals but with control in the sense that the absolute precision for each confidence interval is bounded on the limits with preassigned confidence level. The results of this study may contribute to some situations, for instance, first, we need a statistical method to compare the effectiveness between two alternatives, second, we find the adquate number of replications with any level of absolute precision to avoid the unrealistic cost of running simulation models, third, we are interested in analyzing the standard deviation of the output measure, ..., etc.

• Aerospace Engineering and Technology
• /
• v.4 no.2
• /
• pp.244-251
• /
• 2005

Though it's expected that the demand for commercial UAVs will surpass that for military UAVs in the near future, the lack of regulations and infrastructures prevents commercial UAVs from being operated in the airspace where manned aircraft are operated. In this study, international research trends to prepare for it and the requirements brought up as a result of those research are described.

• Proceedings of the KIEE Conference
• /
• 1998.07g
• /
• pp.2390-2392
• /
• 1998

In this paper, we discuss the development of monitoring system with data process equipment which transfers data from Remote Terminal Unit(RTU) to monitoring computer. The RTUs sense temperature, pressure and PLC(Programmable Logic Controller) nodes conditions of scrubber in semiconductor manufacture processing. The data Process equipment is connected every RTU and a monitoring computer through serial communication. This equipment receives informations from RTU, process data, and transfers them to monitoring computer. To avoid congestion in data communication, task scheduling algorithm used RT O/S(Real-Time Operating System) is embedded in ROM which is a part of data Process equipment.

• Journal of the Optical Society of Korea
• /
• v.18 no.1
• /
• pp.32-36
• /
• 2014

A tangible floating display that can provide different perspective views without special glasses being introduced. The proposed system can display perspective floating images in the space in front of the system with the help of concave mirrors. In order to avoid wearing special equipment to interact and deliver the sense of touch, the proposed system adopted an ultrasound focusing technology. For providing an immersive experience to the viewers, the proposed system consists of a tangible floating display system and a multiple-view imaging system for generating three lenticular displays in front of the users.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.61 no.12
• /
• pp.1911-1919
• /
• 2012

In this paper, we focus on a robotic sealing process in which three robots are used. Each robot can be considered as a 7 axis redundant robot of which the first joint is prismatic and the last 6 joints are revolute. In the factory floor, robot path planning is not a simple problem and is not automated. They need experienced operators who can operate robots by teaching and playing back fashion. However, the robotic sealing process is well organized so the relative positions and orientations of the objects in the floor and robot paths are all pre-determined. Therefore by adopting robotic theory, we can optimally plan robot pathes without using teaching. In this paper, we analyze the sealing robot by using redundant manipulator theory and propose three different methods for path planning. For sealing paths outside of a car body, we propose two methods. The first one is resolving redundancy by using pseudo-inverse of Jacobian and the second one is by using weighted pseudo-inverse of Jacobian. The former is optimal in the sense of energy and the latter is optimal in the sense of manipulability. For sealing paths inside of a car body, we must consider collision avoidance so we propose a performance index for that purpose and a method for optimizing that performance index. We show by simulation that the proposed method can avoid collision with faithfully following the given end effector path.

• Journal of Digital Convergence
• /
• v.12 no.2
• /
• pp.271-276
• /
• 2014

The life-time and performance of a wireless sensor network is closely related to energy-efficiency of sensor nodes. In this paper, to increase energy-efficiency, each sensor node operates in one of three operational modes which are normal, power-saving, and inactive. In normal mode sensor nodes sense and transmit data with normal period, whereas sensor nodes in power-saving mode have three-times longer period. In inactive mode, sensor nodes do not sense and transmit any data, which makes the energy consumption to be minimized. Plus, the proposed algorithm can avoid unnecessary energy consumption by preventing transmitting duplicate sensed data. We implemented and simulated the proposed algorithm using Tiny OS based ZigbeX platfom and NS-2, respectively. Performance evaluation results show that the proposed algorithm can prolong sensor networks' lifespan by efficiently reducing energy consumption and its standard deviation of all sensor nodes.

• Journal of Fashion Business
• /
• v.5 no.1
• /
• pp.97-116
• /
• 2001

Character fashion was already turned up in Egyptian age and nowadays was worn to everybody as regardless of ages, level and sex of people. This paper reviewed character fashion and animation character based on USA and Japan that is outstanding more coming up today and compared and analyzed with our country's situation. Usually, character fashion would give imagnation of products and companies themselves for aesthetic sense and can show possessive feeling and personality. And that mean fashion used by character like pictures and signals(that include words figures and special signals) and these fashion using by animation character was come out in 1929. In spite of third producer, Korea, back from USA and Japan about character fashion, we faced many problems. In order to solve these problems, we must make our own pure character that do not need to pay royalty and must spread marketing strategy with character fashion of more various designs. Therefore we should concentrate for raising high quality works and avoid uneconomic investment and plagiarism and finally we must expand recognition concerning character fashion.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.6 no.1
• /
• pp.426-445
• /
• 2012

Conventional rate control (RC) schemes for H.264 video coding usually regulate output bit rate to match channel bandwidth by adjusting quantization parameter (QP) at fixed full frame rate, and the passive frame skipping to avoid buffer overflow usually occurs when scene changes or high motions exist in video sequences especially at low bit rate, which degrades spatial-temporal quality and causes jerky effect. In this paper, an active content adaptive frame skipping scheme is proposed instead of passive methods, which skips subjectively trivial frames by structural similarity (SSIM) measurement between the original frame and the interpolated frame via motion vector (MV) copy scheme. The saved bits from skipped frames are allocated to coded key ones to enhance their spatial quality, and the skipped frames are well recovered based on MV copy scheme from adjacent key ones at the decoder side to maintain constant frame rate. Experimental results show that the proposed active SSIM-based frameskip scheme acquires better and more consistent spatial-temporal quality both in objective (PSNR) and subjective (SSIM) sense with low complexity compared to classic fixed frame rate control method JVT-G012 and prior objective metric based frameskip method.

• Journal of Information Processing Systems
• /
• v.15 no.4
• /
• pp.797-819
• /
• 2019

Internet of Things (IoT) is the paradigm of network of Internet-connected things as objects that constantly sense the physical world and share the data for further processing. At the core of IoT lies the early technology of radio frequency identification (RFID), which provides accurate location tracking of real-world objects. With its small size and convenience, RFID tags can be attached to everyday items such as books, clothes, furniture and the like as well as to animals, plants, and even humans. This phenomenon is the beginning of new applications and services for the industry and consumer market. IoT is regarded as a fourth industrial revolution because of its massive coverage of services around the world from smart homes to artificial intelligence-enabled smart driving cars, Internet-enabled medical equipment, etc. It is estimated that there will be several dozens of billions of IoT devices ready and operating until 2020 around the world. Despite the growing statistics, however, IoT has security vulnerabilities that must be addressed appropriately to avoid causing damage in the future. As such, we mention some fields of study as a future topic at the end of the survey. Consequently, in this comprehensive survey of IoT, we will cover the architecture of IoT with various layered models, security characteristics, potential applications, and related supporting technologies of IoT such as 5G, MEC, cloud, WSN, etc., including the economic perspective of IoT and its future directions.

• The Journal of Asian Finance, Economics and Business
• /
• v.8 no.11
• /
• pp.277-284
• /
• 2021

This study was conducted to determine the factors affecting employees' engagement in Information Technology (IT) enterprises in Vietnam. Quantitative method was used to test the research model. Research data is collected through a survey of 205 employees working in Ho Chi Minh City - Vietnam IT enterprises. The research results show that all seven factors affecting OC are ability, remuneration, training/development, challenging work, teamwork relationship, company policy, and culture, and work environment all make sense. In which, WOE, TER, REM factors are the three most influential factors, while company CPC, T&D, CHW, ABI have a lower impact. The proposed management implications include building, providing, ensuring a good working environment for employees, building/developing relationships within the company, having a policy of salary, bonus, support, and incentives. In addition, appropriate, competitive remuneration, adequate incentives, and rewards for the efforts that the employee has made, training and development of skills and soft skills suitable for each type of work, development orientations for employees, as well as frequent rotation of positions and jobs, in addition to improving employees' capacity, also avoid causing boredom and loss of motivation at work, thereby increasing OC of employees in IT enterprises in Vietnam.