• Journal of Intelligence and Information Systems
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• v.20 no.3
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• pp.59-76
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• 2014

The revolution of smart media such as smart phone, smart TV and tablets has brought easiness for people to get contents and related information anywhere and anytime. The characteristics of the smart media have changed user behavior for watching the contents from passive attitude into active one. Video is a kind of multimedia resources and widely used to provide information effectively. People not only watch video contents, but also search for related information to specific objects appeared in the contents. However, people have to use extra views or devices to find the information because the existing video contents provide no information through the contents. Therefore, the interaction between user and media is becoming a major concern. The demand for direct interaction and instant information is much increasing. Digital media environment is no longer expected to serve as a one-way information service, which requires user to search manually on the internet finding information they need. To solve the current inconvenience, an interactive service is needed to provide the information exchange function between people and video contents, or between people themselves. Recently, many researchers have recognized the importance of the requirements for interactive services, but only few services provide interactive video within restricted functionality. Only cooking domain is chosen for an interactive cooking video query service in this research. Cooking is receiving lots of people attention continuously. By using smart media devices, user can easily watch a cooking video. One-way information nature of cooking video does not allow to interactively getting more information about the certain contents, although due to the characteristics of videos, cooking videos provide various information such as cooking scenes and explanation for each recipe step. Cooking video indeed attracts academic researches to study and solve several problems related to cooking. However, just few studies focused on interactive services in cooking video and they still not sufficient to provide the interaction with users. In this paper, an interactive cooking video query service system with linked data to provide the interaction functionalities to users. A linked recipe schema is used to handle the linked data. The linked data approach is applied to construct queries in systematic manner when user interacts with cooking videos. We add some classes, data properties, and relations to the linked recipe schema because the current version of the schema is not enough to serve user interaction. A web crawler extracts recipe information from allrecipes.com. All extracted recipe information is transformed into ontology instances by using developed instance generator. To provide a query function, hundreds of questions in cooking video web sites such as BBC food, Foodista, Fine cooking are investigated and analyzed. After the analysis of the investigated questions, we summary the questions into four categories by question generalization. For the question generalization, the questions are clustered in eleven questions. The proposed system provides an environment associating UI (User Interface) and UX (User Experience) that allow user to watch cooking videos while obtaining the necessary additional information using extra information layer. User can use the proposed interactive cooking video system at both PC and mobile environments because responsive web design is applied for the proposed system. In addition, the proposed system enables the interaction between user and video in various smart media devices by employing linked data to provide information matching with the current context. Two methods are used to evaluate the proposed system. First, through a questionnaire-based method, computer system usability is measured by comparing the proposed system with the existing web site. Second, the answer accuracy for user interaction is measured to inspect to-be-offered information. The experimental results show that the proposed system receives a favorable evaluation and provides accurate answers for user interaction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.9
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• pp.486-491
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• 2017

The water discharged from sewage treatment plants has been considered to be useless, due to itslack of economic utility for small hydro power generation. Considering that most sewage treatment facilities have a water head of less than 2 meters and their flow rate is constant, it is necessary to develop a small hydro power generation device capable of maintaining stable power generation and efficiency. This paper presents the development of anintegrated small hydro power generation system and presents its performance evaluation and results. Then, the economics and use of the system for practical applications are suggested. As a result, it is foundthat the generator efficiency is 92%, the electric energy produced is 10kWh and the economic efficiency, as described by the B/C ratio,is 1.0 or more. Particularly, if the operating level of the generation device is maintained at 80% or more of the rated power, it is possible to secure its economic efficiency and, after 23 years, the investment cost will bereturned. The integrated hydro power generation device is expected to have a positive effect not only in terms of the water discharged from the sewage treatment plant, but also in terms of facilities capable of securing similar flow characteristics.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.29 no.6
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• pp.305-314
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• 2017

Ocean wave energy harvesting is still too expensive despite developing a variety of wave energy converter (WEC) devices. For the cost-effective wave energy harvesting, it can be an effective measure to use existing breakwaters or newly installed breakwaters for both wave control and energy harvesting purposes. In this study, we investigated the functionality of both breakwater and wave-power generator for the oscillating water column (OWC)-type wave energy converter (WEC) installed in a pneumatic floating breakwater, which was originally developed as a floating breakwater. In order to verify the performance of the breakwater as a WEC, the air flow velocity from air-chamber to WEC has to be evaluated properly. Therefore, air flow velocity, wave transformation and motion of floating structure was numerically implemented based on BEM from linear velocity potential theory without considering the compressibility of air within the chamber. Air pressure, meanwhile, was assumed to be fluctuated by the motions of structure and the water level change within air-chamber. The validity of the obtained values can be determined by comparing the previous results from the numerical analysis for different shapes. Based on numerical model results, wave transformation characteristics around OWC system mounted on the fixed and floating breakwaters, and motions of the structure with air flow velocities are investigated. In summary, all numerical results are almost identical to the previous research considering air compressibility. Therefore, it can be concluded that this analysis not considering air compressibility in the air chamber is more efficient and practical method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.6
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• pp.573-582
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• 2010

In this paper, X-band transceiver for high resolution wideband SAR systems is designed and fabricated. Also as a technique for enhancing the performance, error compensation algorithm is presented. The transceiver for SAR system is composed of transmitter, receiver, switch matrix and frequency generator. The receiver especially has 2 channel mono-pulse structure for ground moving target indication. The transceiver is able to provide the deramping signal for high resolution mode and select the receive bandwidth for receiving according to the operation mode. The transceiver had over 300 MHz bandwidth in X-band and 13.3 dBm output power which is appropriate to drive the T/R module. The receiver gain and noise figure was 39 dB and 3.96 dB respectively. The receive dynamic range was 30 dB and amplitude imbalance and phase imbalance of I/Q channel was ${\pm}$0.38 dBm and ${\pm}$3.47 degree respectively. The transceiver meets the required electrical performances through the individual tests. This paper shows the pulse error term depending on SAR performance was analyzed and range IRF was enhanced by applying the compensation technique.

• The Journal of the Acoustical Society of Korea
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• v.30 no.1
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• pp.9-16
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• 2011

When a hydrofoil ship plies at high speed, there exist possibilities of collision with ocean mammals dwelling near the surface. An active sonar located within the immersed hydrofoil structure that provides the lift for the vessel, can be used for early warning of their presence. The proper functioning of the active sonar system depends on its ability to reject noise and pick up the target signal. In this article, we measured the noise on a hydrofoil of an operating ship with two flush-mounted hydrophones. The measurements were conducted for the purpose of (1) identifying the effect of operating state of machinery likes engine, cooler and generator (2) observing the change of noise depending on the measuring position (3) observing the change of noise with increasing ship speed. To verify our experiment, experiments were performed three times and the measured results are compared with other investigations and they show similarity to each other. The results are analyzed with frequency domain in order to apply to operating active sonar detecting system and focus on high frequency band within sonar's operating frequency region. Through these experiments and analysis, it is expected that we can identify the generated noise around hydrofoil where active sonar is installed and these results lead us to design active sonar that could distinguish target signal from noise more effectively.

• The KIPS Transactions:PartB
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• v.9B no.6
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• pp.775-782
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• 2002

As electronic commerce systems have been widely used, the necessity of adaptive e-commerce agent systems has been increased. These kinds of agents can monitor customer's purchasing behaviors, clutter them in similar categories, and induce customer's preference from each category. In order to implement our adaptive e-commerce agent system, we focus on following 3 components-the monitor agent which can monitor customer's browsing/purchasing data and abstract them, the conceptual cluster agent which cluster customer's abstract data, and the customer profile agent which generate profile from cluster, In order to infer more accurate customer's preference, we propose a 2 layered structure consisting of conceptual cluster and inductive profile generator. Many systems have been suffered from errors in deriving user profiles by using a single structure. However, our proposed 2 layered structure enables us to improve the qualify of user profile by clustering user purchasing behavior in advance. This approach enables us to build more user adaptive e-commerce system according to user purchasing behavior.

• Journal of Bio-Environment Control
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• v.22 no.3
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• pp.220-227
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• 2013

This study examined the electric power quantity derived from solar radiation after installing a photovoltaic power generation system on the rooftop of building adjacent to a greenhouse with a view to reducing the operating expenses of the greenhouse by securing electric energy required to run it. Results of the study can be summed up as follows: The maximum, mean, and minimum solar radiation on the horizontal plane was $26.1MJ{\cdot}m^{-2}$, $14,0MJ{\cdot}m^{-2}$, and $0.6MJ{\cdot}m^{-2}$, respectively and individual the daily electric energy generated was about 6.1 kWh, 3.7 kWh, and 0.01 kWh. The cumulative total amounts of solar radiation and electric energy was about $4,378.2MJ{\cdot}m^{-2}$ and 1,163.2 kWh, respectively. Maximum, mean and minimum cumulative electric energy consumed through each load respectively was 4.5 kWh, 2.4 kWh, and 0.0 kWh and the cumulative electric energy were 739.2 kWh, which accounted for about 63.5% of generated power. In case of the mean amount of power consumption of the system used for this study, the small capacity of heater and the short operating hours meant there was enough power; while big capacity of heater led to a shortage, and if the array surface temperature increased relatively, the energy became proportionate to solar radiation and generated power does not increase. The correlation coefficient between the two factors was 0.851, which indicates a high correlation coefficient.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.235-240
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• 2020

This study evaluated the improvements for circuits of a combat vehicle distribution box to reduce the noise generated in electromagnetic compatibility (EMC) testing. An analysis of the distribution boxes that failed the standard revealed the conducted noise generated from the converter and semiconductor switching elements on the circuit board. The distribution box transfers power from the generator and battery to the cooling system of a combat vehicle to keep turning the air conditioner on and off. Two methods were proposed to overcome this problem: a passive filter was added to the circuit board for the first method, and the converter and switching elements were replaced with the relays for the second method. Both methods were effective in reducing noise, but a greater improvement was obtained from the second method. The second method was applied to a combat vehicle system and was found to be suitable according to the EMC standards.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.4 no.2
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• pp.208-223
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• 1994

The purpose of this study was to evaluate the efficiency of diffusive(or passive) sampler in measuring airbone organic solvents. Diffusive samplers are generally simple in construction and do not require power for operation. The efficiency of the diffusive samplers has not sufficiently been investigated in Korea. Three types of samplers were studied in this study. The sampling and analytical results by passive samplers were compared with results by charcoal tube method recommended by NIOSH(National Institute for Occupational Safty and Health). The following characteristics are identified and studied as critical to the performance passive monitors; recovery, reverse diffusion, storage stability, accuracy and precision, face velocity and humidity, n-Hexane, TCE(trichloroethylene) and toluene were used as test vapors. A dynamic vapor exposure system consisting of organic vapor generator and sampling chamber for evaluating diffusive samplers are made. The results of the study are summarized as follows. 1. NIOSH recommands that the overall accuracy of a sampling method in the range of 0.5 to 2.0 times the occupational health standard should be ${\pm}25$ percent for 95 percent confidence level. Among three types of diffusive samplers, sampler A has permeation membrane and samplers Band C have diffusive areas, samplers A and B met the criterion that overall accuracy for 95% confidence level of the samplers were within ${\pm}25$ percent of the reference value. Sampler C had overall accuracy ${\pm}9.6%$ and ${\pm}11.8%$ in hexane and TCE, respectively. The concentration of toluene was overestimated in sampler C with overall accuracy of ${\pm}43.9%$. 2. The desorption efficiencies of diffusive samplers were 96-107%. 3. There was no significant sampe loss during four weeks of storage both with and without refrigeration. 4. There was no significant reverse diffusion, when the samplers were exposure to clean air for 2 hours after sampling for 2 hours at the level of 2 TLY. 5. In case of 8 hours sampling, relative differences(RD) of concentrations between charcoal tube method and diffusive method were 15-39%, 13-46%, and 4-35% for sampler A, B and C, respectively. The performance was poor in 8 hours sampling for multiple substance monitors. 6. At high velocity(100 cm/sec), samplers B and C overestimated the concentrations of organic vapors, and sampler A with permeation membrance gave better results. 7. At 80% relative humidity, samplers showed no siginificant effect. Low humidity also did not affect the diffusive samplers.

• Journal of KIISE:Software and Applications
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• v.32 no.3
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• pp.202-214
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• 2005

The semantic web is the web paradigm that represents not general link of documents but semantics and relation of document. In addition it enables software agents to understand semantics of documents. We propose a semantic search based on inference with ontologies, which has the following characteristics. First, our search engine enables retrieval using explicit ontologies to reason though a search keyword is different from that of documents. Second, although the concept of two ontologies does not match exactly, can be found out similar results from a rule based translator and ontological reasoning. Third, our approach enables search engine to increase accuracy and precision by using explicit ontologies to reason about meanings of documents rather than guessing meanings of documents just by keyword. Fourth, domain ontology enables users to use more detailed queries based on ontology-based automated query generator that has search area and accuracy similar to NLP. Fifth, it enables agents to do automated search not only documents with keyword but also user-preferable information and knowledge from ontologies. It can perform search more accurately than current retrieval systems which use query to databases or keyword matching. We demonstrate our system, which use ontologies and inference based on explicit ontologies, can perform better than keyword matching approach .