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

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.1
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• pp.197-209
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• 2015

The issue of information security within an organization began to be recognized as risk of the organization. Because of this, not only ISO(Information Security Officer) but an executive or CEO were forced to resign. In addition, it brought about heavy financial damage to the company and made the company difficult to restore trust to customers. At a time when inadvertent disclosure of personal information has become accepted as a matter of survival because of having a bad effect within an organization, how the information security specialist causes influence on information protection level of the organization. For these reasons, targeting the information security specialists of various industry sectors, we'll analyse how task performance rate of the information security specialist within an organization cause influence to the information security level. The goal of this study is for the company to raise the task proportion of information security specialist and to improve the information protection level of the organization.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.5
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• pp.487-495
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• 2012

In this paper, a Smart Home Service Robot, McBot II, which performs mess-cleanup function etc. in house, is designed much more optimally than other service robots. It is newly developed in much more practical system than McBot I which we had developed two years ago. One characteristic attribute of mobile platforms equipped with a set of dependent wheels is their omni- directionality and the ability to realize complex translational and rotational trajectories for agile navigation in door. An accurate coordination of steering angle and spinning rate of each wheel is necessary for a consistent motion. This paper develops trajectory controller of 3-wheels omni-directional mobile robot using fuzzy azimuth estimator. A specialized anthropomorphic robot manipulator which can be attached to the housemaid robot McBot II, is developed in this paper. This built-in type manipulator consists of both arms with 4 DOF (Degree of Freedom) each and both hands with 3 DOF each. The robotic arm is optimally designed to satisfy both the minimum mechanical size and the maximum workspace. Minimum mass and length are required for the built-in cooperated-arms system. But that makes the workspace so small. This paper proposes optimal design method to overcome the problem by using neck joint to move the arms horizontally forward/backward and waist joint to move them vertically up/down. The robotic hand, which has two fingers and a thumb, is also optimally designed in task-based concept. Finally, the good performance of the developed McBot II is confirmed through live tests of the mess-cleanup task.

• 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.

• Journal of KIISE:Information Networking
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• v.33 no.2
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• pp.113-130
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• 2006

Recently with the explosive growth of Internet applications, the attacks of hackers on network are increasing rapidly and becoming more seriously. Thus information security is emerging as a critical factor in designing a network system and much attention is paid to Network Intrusion Detection System (NIDS), which detects hackers' attacks on network and handles them properly However, the performance of current intrusion detection system cannot catch the increasing rate of the Internet speed because most of the NIDSs are implemented by software. In this paper, we propose a new high performance network intrusion using Network Processor. To achieve fast packet processing and dynamic adaptation of intrusion patterns that are continuously added, a new high performance network intrusion detection system using Intel's network processor, IXP1200, is proposed. Unlike traditional intrusion detection engines, which have been implemented by either software or hardware so far, we design an optimized architecture and algorithms, exploiting the features of network processor. In addition, for more efficient detection engine scheduling, we proposed task allocation methods on multi-processing processors. Through implementation and performance evaluation, we show the proprieties of the proposed approach.

• Journal of Drive and Control
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• v.21 no.2
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• pp.23-29
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• 2024

Potatoes are one of the world's four major crops, and domestic consumption is currently increasing in Korea. However, the mechanization rate of potatoes is very low, and especially, harvesting is the most labor-intensive task in potato production. In Korea, potato-collecting work depends on manpower, so it is necessary to develop a gathering-type harvester that can be used for processes from digging to harvesting. Therefore, in this study, a self-propelled-type potato harvester was developed, and its performance was analyzed to mechanize harvesting. The potato harvester was developed to have a crawler-type driving part with a 60 hp diesel engine and consisted of a digging part that digs potatoes from the ground, a vertical transporting part that transfers the dug potatoes to the height of the collection bag, a separating part that separates debris, such as stones and soil, and a collecting part that loads the collection box. A field test of the potato harvester was conducted, and performance was evaluated by the damage, loss, and debris mixing proportions, which were 2.5%, 2.8%, and 2.6%, respectively. The working capacity was 1.2 h/10 a. The economic analysis results showed that the cost of harvesting work could be reduced by 12.7% compared to manual harvesting.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.1
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• pp.14-22
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• 2001

Off-line handwritten numeral recognition is a very difficult task and hard to achieve high recognition results using a single feature and a single classifier, since handwritten numerals contain many pattern variations which mostly depend upon individual writing styles. In this paper, we propose handwritten numeral recognition system using hybrid features and combined classifier. To improve recognition rate, we select mutually helpful features -directional features, crossing point feature and mesh features- and make throe new hybrid feature sets by using these features. These hybrid feature sets hold the local and global characteristics of input numeral images. And we implement combined classifier by combining three neural network classifiers to achieve high recognition rate, where fuzzy integral is used for multiple network fusion. In order to verify the performance of the proposed recognition system, experiments with the unconstrained handwritten numeral database of Concordia University, Canada were performed. As a result, our method has produced 97.85% of the recognition rate.

• Journal of KIISE:Information Networking
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• v.32 no.4
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• pp.471-482
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• 2005

The high-speed network permits Grid computing to handle large problem of management areas and share various computational resources. As there are many resources and changes of them in Grid computing, the resources should be detected effectively and matched correctly with tasks to provide high performance. In this paper, we propose a mechanism that maximizes the performance of Grid computing systems. According to a priority, grade and site of heterogeneous resources, we assign tasks to those resources. Initially, a volunteer's priority and ranking are determined by static information like as CPU speed, RAM size, storage size and network bandwidth. And then, the rank of resources is decided by considering dynamic information such as correctness, response time, and error rate. We find that overall Grid system performance is improved and high correctness using resource reallocation mechanism is achieved.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.4
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• pp.30-37
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• 2011

This paper proposes a language set of hand motions for enhancing the performance of vision-based hand signal recognizer. Based on the statistical analysis of the angular tendency of hand movements in sign language and the hand motions in practical use, we construct four motion primitives as building blocks for basic hand motions. By combining these motion primitives, we design a discernable 'fundamental hand motion set' toward increasing the hand signal recognition. To demonstrate the validity of proposed designing method, we develop a 'fundamental hand motion set' recognizer based on hidden Markov model (HMM). The recognition system showed 99.01% recognition rate on the proposed language set. This result validates that the proposed language set enhances discernaility among the hand motions such that the performance of hand signal recognizer is improved.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.7C
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• pp.616-626
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• 2007

In spatially multiplexed MIMO systems that enable high data rate transmission over wireless communication channels, the spatial demultiplexing at the receiver is a challenging task, and various demultiplexing methods have been developed recently by many researchers. Among the previous methods, maximum likelihood detection with QR decomposition and M-algorithm (QRM-MM)), and sphere decoding (SD) schemes have been reported to achieve a (near) maximum likelihood (ML) performance. In this paper, we propose a novel signal detection method that achieves a near ML performance in a computationally efficient manner. The proposed method is demonstrated via a set of computer simulations that the proposed method achieves a near ML performance while requiring a complexity that is comparable to that of the conventional MMSE-OSIC. We also show that the log likelihood ratio (LLR) values for all bits are obtained without additional calculation but as byproduct in the proposed detection method, while in the previous QRM-MLD, SD, additional computation is necessary after the hard decision for LLR calculation.