• Journal of Korea Multimedia Society
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• v.13 no.11
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• pp.1715-1727
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• 2010

Although a hand haptic interaction which provides direct and natural sensation is the most natural way of interacting with VR environment, the hand haptic interaction has still limitations with respect to the complexity of articulated hand and related hardware capabilities. Particularly, virtual assembly simulation which refers to the verification process of digital mockup in product development lifecycle is one of the most challenging topics in virtual reality applications. However, hand haptic interaction is considered as a big obstacle, because difficulty initial grasping and non-dextrous manipulation remain as unsolved problems. In this paper, we propose that common hand haptic interactions involves two separate stages with different aspects. We present the hand haptic interaction method enables us to stably grasp a virtual object at initial grasping and delicately manipulate an object at task operating by one's intention. Therefore, proposed method provides the robustness using grasping quality and dextrous manipulation using physically simulation. We conducted experiments to evaluate the effectiveness of our proposed method under different display environments -monoscopic and stereoscopic. From 2-way ANOVA test, we show that the proposed method satisfies two aspects of hand haptic interaction. Finally, we demonstrated an actual application of various assembly simulation for relatively complex models.

• Cartoon and Animation Studies
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• s.40
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• pp.443-476
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• 2015

The university e-learning classes give a major focused on practical training in the art and design field are opened such as theory classes. The cyber universities that fully gives on-line classes even open as theory classes. They speak about difficulty and limitation of operating cyber class with practice. So, many of them organize off-line special lecture at the classroom in weekend. In the reason of studying that has the constraints of time and space, the student wastage rates in cyber universities are going higher. This research focused on giving an efficient e-learning practice environment in college e-learning courses, and operated scholastic achievement test between the augmented reality(AR) based practice education and the existing classroom based practice education. The subjects of study were totally 84 people who are the freshmen of the design department in the two-year diploma course college. They were divided 3 groups which one was treated AR based practice e-learning and two others groups were existing classroom based practice. Each of the group took the same treated lecture during 7 weeks. The first of the outcome was the AR based practice e-learning was more effective than existing classroom based practice on the side of scholastic achievement. The second, the AR based practice e-learning aroused increasing in the interest in class on the side of attribute factors. The third, the AR based practice e-learning group made higher level of studying immersion than others. In consideration of this experiment was processed in the regular college academic course, the finding by this research shows AR based major practice e-learning is an alternative lecturing strategy what can be supplemented existing classroom based academic teaching methods.

• Journal of the Korea Organic Resources Recycling Association
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• v.23 no.2
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• pp.47-52
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• 2015

A microbial fuel cell (MFC) is a device that can be obtained electricity from a variety of organic through the catalytic reaction of the microorganism. The MFC can be applied to various fields, and research is required to promote the performance of the microbial fuel cell for commercialization. The lower performance of an MFC is due to oxygen reduction at the cathode and the longer time of microbial degradation at anode. The MFC amount of power is sufficient but, in consideration of many factors, as a renewable energy, now commonly power density as compared to Nafion117 it is an ion exchange membrane used is PP (Poly Propylene) from 80 to about 11 fold higher, while reducing the cost to process wastewater is changed to a microporous non-woven fabric of a low cost, it may be energy-friendly environment to generate electricity. All waste, in that it can act as a bait for microorganisms, sustainability of the microbial fuel cell is limitless. The latest research on the optimization and performance of the operating parameters are surveyed and through the SSaM-GG(Smart, Shared, and Mutual- Green Growth) or GG-SSaM(Green Growth - Smart, Shared, and Mutual) as the concept of sustainable development in MFC, the middle indices are developed in this study.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.12
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• pp.2187-2195
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• 2000

A water treatment system using membrane separation technology can provide stable effluent quality and its maintenance is relatively easy comparing to the conventional water treatment system. In addition, the membrane filtration system is very compact such that it can replace existing water treatment processes of coagulation/sedimentation/filtration by only one process. However, a major problem associated with membrane filtration is flux decline with operating time due to concentration polarization and fouling, so a systematic study on evaluation of long-term filtration performance is necessary. A membrane filtration system using tubular type ultrafiltration membranes with MWCO of 30.000 Da was constructed for this study and it had been operated in a feed-and-discontinuous bleed mode. Flux was stabilized after operation of 1.500 hours and maintaining above 25 LMH until 4.000 hours. Contaminants causing SS and turbidity were almost completely removed while the $UV_{260}$ and DOC removals were 55% and 49%, respectively. A simple mass balance equation was developed to predict maximum concentrations of SS, turbidity, $UV_{260}$ and DOC in a operation cycle. For SS and turbidity the measured max, concentrations in each cycle agree well with the predicted values while the measured max, concentrations of $UV_{260}$ and DOC were 59% and 37% of the predicted values, respectively.

• Journal of Navigation and Port Research
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• v.32 no.8
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• pp.667-674
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• 2008

In this paper, operational problems of Busan Port and competitiveness deciding factors are analyzed by field data research and interview with employees in shipping companies and terminal operation companies. In the analysis, the problems Busan Port currently has are identified as follows: 1) low price competitiveness, 2) Lack of new port back facilities and connecting transportion system 3) Lack of operation ability of container terminal 4) Inefficient pour labor supply system. In order to strengthen the competitiveness and leap up to a hub port in North East Asia, Busan port is investigated to enhance below requirements. 1) Hiring more equipment and increase productivity in terminal 2) Integrating terminal operation companies to react maximization of vessel 3) Maintaining cost advantages 4)Proactively inviting global carriers to participate in the terminal operation 5)Making business environment for Global Terminal Operator to participate in the terminal operation in order to take advantage of their global marketing power.

• The KIPS Transactions:PartC
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• v.13C no.6 s.109
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• pp.709-716
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• 2006

According to the increase of various AV media devices and contents in the digital home, the DLNA becomes to play an important role as the interoperability standard between then Since this guideline only focuses on the interoperability among home networked devices, media players, and media contents existing inside of the homenetwork, there is no retrieval and transmission method for sharing multimedia contents located over several homes via Internet. Additionally, this guideline lets device-detection and notification messages to be transmitted using W multicast methods, and current Internet environment cannot guarantee consistent IP multicast services, it has the limitation that it cannot retrieve and control DLNA devices in other digital homes remotely via the Internet. Therefore, in this paper, we propose the IHM(Inter-Home Media) proxy system and its operating mechanism to provide a way of sharing media contents distributed over multiple DLNA-based homes, through analyzing these limitations and building up a sharing method for A/V media contents distributed over the DLNA homes based on the dynamic or private IP networks. Our method removes the limitation on the user locations through sharing distributed media contents, and also makes cost-downs for storing media contents, from the view point of individual residents.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.5
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• pp.251-259
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• 2014

In this paper, we propose Low Energy Service Discovery (LESD) protocol for common discovery mode of IEEE 802.15.8 Peer Aware Communications (PAC). In order to minimize power consumption, Basic Repetition Block (BRB) is defined. Device is able to select operating mode and synchronize other devices through it. Proposed MAC procedure is Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) based on overhearing technique. Even if device has not been received response signal since transmitted request signal, it is able to discover other devices of same group through the overhearing technique. IEEE 802.15.8 PAC has required that performances of common discovery mode are presented about discovered devices during the simulation time, discovery latency and average power consumption. By considering the number of devices per group and channel environment, two scenarios are evaluated through system level simulation and the simulation results of proposed scheme are compared with CSMA/CA in same simulation conditions. As a result, proposed scheme is able to get high energy efficiency of devices as well as increase the number of discovered devices during simulation time when the longer the number of devices is distributed over a limited area.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.208-213
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• 2016

In the fourth industrial revolution, customization is becoming a conversation topic in various domains. Industry 4.0 applies cyber-physical systems (CPS), the Internet of Things (IoT), and cloud computing to manufacturing businesses. One of the main phrases in Industry 4.0 is mass customization. Optimized products or services are developed and provided through customization. Therefore, the competitiveness of a product can be enhanced, and satisfaction is improved. In particular, as IoT technology spreads, customization is an essential aspect of smooth service connections between various devices or things. Customized services in mobile applications are assembled and operate in various mobile devices in the mobile environment. Therefore, this paper proposes a method for improving customized cloud server-based mobile architectures, processes, and metrics, and for measuring the performance improvement of the customized architectures operating in various mobile devices based on the Android or IOS platforms. We reduce the total time required for customization in half as a result of applying the proposed customized architectures, processes, and metrics in various devices.

• Journal of Korea Water Resources Association
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• v.53 no.4
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• pp.293-301
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• 2020

This study determined appropriate threshold level (cumulative period and percentage) of precipitation for drought management in dam basin. The 5 dam basins were selected, the daily dam storage level and daily precipitation data were collected. MAP (Mean Areal Precipitation was calculated by using Thiessen polygon method, and MAP were converted to accumulated values for 6 cumulative periods (30-, 60-, 90-, 180-, 270-, and 360-day). The correlation coefficient and ratio of variation coefficient between storage level and MAP for 6 cumulative periods were used to determine the appropriate cumulative period. Correlation of cumulative precipitation below 90-day was low, and that of 270-day was high. Correlation was high when the past precipitation during the flood period was included within the cumulative period. The ratio of variation coefficient was higher for the shorter cumulative period and lower for the longer in all dam, and that of 270-day precipitation was closed to 1.0 in every month. ROC (Receiver Operating Characteristics) analysis with TLWSA (Threshold Line of Water Supply Adjustment) was used to determine the percentage of precipitation shortages. It is showed that the percentage of 270-day cumulative precipitation on Boryung dam and other 4-dam were less than 90% and 80% as threshold level respectively, when the storage was below the attention level. The relationship between storage and percentage of dam outflow and precipitation were analyzed to evaluate the impact of artificial dam operations on drought analysis, and the magnitude of dam outflow caused uncertainty in the analysis between precipitation and storage data. It is concluded that threshold level should be considered for dam drought analysis using based on precipitation.

• Membrane Journal
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• v.25 no.4
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• pp.301-309
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• 2015

Importance of pretreatment for seawater desalination is growing rapidly. Proper selection of pretreatment is critical for the successful, long-term operation in the seawater desalination plant such as seawater reverse osmosis (SWRO). The purposes of seawater pretreatment are to remove particulate, colloidal materials, organic, inorganic materials, microorganisms and their by-products present in the seawater, and thus to improve the performance of seawater desalination systems. However, pretreatment is most challenging for designing and operating seawater desalination plants because of fluctuations of water qualities, site specifications and wide ranges of target materials present in the seawater to be treated. In addition, it is also becoming evident increasingly that microscopic algae are a major cause of operational problems, for example, membrane fouling which is long-standing problem in SWRO process. Pretreatment strategies prior to the operation of seawater desalination technologies should be even more complicated by algae blooms and release of their harmful by-products in marine environment. This paper reviews the roles of various pretreatment methods in seawater desalination process. Benefits and drawbacks are described, which should be taken into account in future studies on selecting pretreatment for seawater desalination process.