• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.9B
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• pp.1295-1304
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• 2010

This paper proposes a fault-tolerant data aggregation which provides energy efficient and reliable data collection in wireless sensor networks. The traditional aggregation scheme does not provide the countermeasure to packet loss or the countermeasure scheme requires a large amount of energy. The proposed scheme applies caching and re-transmission based on the track topology to the adaptive timeout scheduling. The proposed scheme uses a single-path routing based on the traditional tree topology at normal, which reduces the dissipated energy in sensor nodes without any countermeasure against packet loss. The proposed scheme, however, retransmits the lost packet using track topology under event occurrences in order to fulfill more accurate data aggregation. Extensive simulation work under various workloads has revealed that the proposed scheme decrease by 8% in terms of the dissipated energy and enhances data accuracy 41% when the potential of event occurrence exists as compared with TAG data aggregation. And the proposed scheme decrease by 53% in terms of the dissipated energy and shows a similar performance in data accuracy when the potential of event occurrence exists as compared with PERLA data aggregation.

• Spatial Information Research
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• v.9 no.2
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• pp.341-352
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• 2001

This study was carried out to developed that appraisement model of Potential Productivity Index(PPI). PPI model was used Farmland Productivity Index(FPI) and Labor Productivity Index(LPI) by GIS, and PPI model applied to farm land consolidation region which has been completed recently. FPI was determined by overlapping Poly Grid of the soil properties at the analyzed project region. LPI was estimated by addition productive wages ratio of total direct productive cost. Addition productive wages determined by GIS Network analysis GIS Network analysis of working distance between farm house to paddy and each paddy. PPI variation of each the analyzed paddy of Masu and Weoncheon region was 0.967~0.780 respectively, and could be showed relative largely PPI value. PPI will provide basic element for large scaling and gathering of farm land and a substitute lot of farm land consolidation, and will be maximize productivity of paddy.

• Fashion & Textile Research Journal
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• v.22 no.4
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• pp.432-445
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• 2020

This study identified the utilization characteristics of individual fashion taste expression on Instagram, and examined the impact of the use of the media on the formation and change of fashion taste. The research method conducted 1:1 indepth interviews with 19 people in their 20s and 30s using 501 images for analysis. The results of this study are as follows. Posting, searching, and reading behavior on Instagram were identified in three dimensions (self-expression, information gathering, and relationship orientation). In the image of self-expression, clothes were displayed at the time so that they could be checked and applied in other ways. Accumulated posts inspired people to look back on past styles and use them to reflect on the present. A media environment that was constantly exposed to information in real time allowed people to try various styles by imitating other users' posts and share in a process of creatively exploring styles to help organize fashion tastes developmentally. Participants had selective relationships with people of similar tastes who experienced the pleasure of enjoying through the exchange of tastes in fashion. These taste mates directly influenced the formation or change of tastes, serving as a criteria for styles or presenting new styles. In this study, fashion taste was formed by individual efforts of pursuit (not a collective social class choice) and was a continuous process of constantly changing that also exploring discriminatory styles.

• Journal of Convergence for Information Technology
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• v.8 no.2
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• pp.67-75
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• 2018

We sought to develop a multi-dimensional tool for measuring and understanding nurse fatigue. The participants were 301 nurses working in four hospitals in Seoul, South Korea. Basic items were developed after a preliminary literature review, and content validity was verified by a group of experts. The first 52 items from which the fatigue measurement tool was to be developed were tested for construct validity and were reduced via factor analysis to 31 items. Following a confirmatory factor analysis, the items were further reduced to 23 items in three categories: physical, mental, and emotional. A confirmatory factor analysis found the items to be adequate. The fatigue scale was found to have high construct validity and reliability. This scale is expected to serve as a preliminary data-gathering tool to assess the level of nurse fatigue and to develop interventions to alleviate it.

• International Commerce and Information Review
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• v.13 no.4
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• pp.101-124
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• 2011

This paper is framed for analyzing what the most significant factors are in Turkey, where the Korean investing enterprises should overcome and accomodate to the various barriers of management, especially in terms of network construction. The main purpose of this research is to test empirically some connections of between the managing strategy of network competitiveness by Korean enterprises and the management performances of Korean ones in Turkey while this is composed of two stages. First, the study model is planned by discussing relevant theories, previous studies and the current investment circumstances in local Turkey. Second, the survey of Korean enterprises participated in investment activities in there is practiced by gathering questionnaires. The strategic method of structural equation modeling is implemented to testing some hypotheses. Summing up partially, to maximize profits growth, Korean enterprises have been making application of the internal worker controlling as the means of network competitive advantages.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.7
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• pp.223-229
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• 2014

The acoustic cleaning system is widely used to remove foreign materials in factories, such as thermal power plants and incinerators. However, the acoustic cleaning systems tend to be clogged by foreign materials. In this paper, we develop a wireless sensor network for the sound wave detection in order to monitor proper operations in the acoustic cleaning systems. We observe that the developed wireless sensor network for the wave detection shows a stable operation in various industrial environments of wide temperature ranges. We also develop a data gathering device, which displays the current status of the sound generator and several values detected from the wireless sensor.

• Journal of the Korea Society of Computer and Information
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• v.25 no.2
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• pp.105-111
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• 2020

In this paper, we propose a scheme that minimizes the energy imbalance problem of solar-powered wireless sensor network (SP-WSN) using both a mobile sink capable of wireless power transfer and an efficient clustering scheme (including cluster head election). The proposed scheme charges the cluster head using wireless power transfer from a mobile sink and mitigates the energy hotspot of the nodes nearby the head. SP-WSNs can continuously harvest energy, alleviating the energy constraints of battery-based WSN. However, if a fixed sink is used, the energy imbalance problem, which is energy consumption rate of nodes located near the sink is relatively increased, cannot be solved. Thus, recent research approaches the energy imbalance problem by using a mobile sink in SP-WSN. Meanwhile, with the development of wireless power transmission technology, a mobile sink may play a role of energy charging through wireless power transmission as well as data gathering in a WSN. Simulation results demonstrate that increase the amount of collected data by the sink using the proposed scheme.

• Journal of the Korea Computer Graphics Society
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• v.16 no.3
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• pp.41-48
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• 2010

Photon mapping is a traditional global illumination method using many photons emitted from the light source for photo-realistic rendering. However, this method needs a lot of resources to perform tracing of millions of photons. Progressive photon mapping solves this problem. Typical progressive photon mapping performs ray tracing at first to find the hit points on diffuse surface of objects. Next, light source repeatedly emits a small number of photons in photon tracing pass, and power of photons in each sphere that has a fixed radius with the hit points in the center is accumulated. This method requires less resources than previous photon mapping, but it spends much time for gathering enough photons since each of photons progresses through a random direction and rendering high quality image. To improve the method, we propose photon probing that calculates variance of photons in the sphere and controls radius of sphere. In addition, we apply cone filter in radiance estimation step for reducing aliasing at the edges in result image.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.95-98
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• 2006

Data collected by sensors in field are transmitted to the base station gathering all of data. Because sensors have to gather data in surroundings and periodically transmit data to the base station, it makes energy consumed much. In this paper, we propose the scheme that is to avoid traffic congestion with achievement of energy efficiency, so collected data is transmitted efficiently. This is to adjust transmission rate differently in case of increasing or decreasing traffic and minimize the energy consumption with setting ideal options up basic CSMA(Carrier Sense Multiple Access) protocol in each sensor. Through the simulation, we find the ideal CSMA options and apply the proposed scheme of traffic control mechanism to them, then show energy efficiency and effective traffic control mechanism.

• Journal of KIISE:Databases
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• v.35 no.1
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• pp.84-95
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• 2008

Wireless sensor networks have recently emerged as a platform for several applications. By deploying wireless sensor nodes and constructing a sensor network, we can remotely obtain information about the behavior, conditions, and positions of objects in a region. Since sensor nodes operate on batteries, energy-efficient mechanisms for gathering sensor data are indispensable to prolong the lifetime of a sensor network as long as possible. In this paper, we propose a novel clustering algorithm that distributes the energy consumption of a cluster head. First, we analyze the energy consumption if cluster heads and divide each cluster into a collection layer and a transmission layer according to their roles. Then, we elect a cluster head for each layer to distribute the energy consumption of single cluster head. In order to show the superiority of our clustering algorithm, we compare it with the existing clustering algorithm in terms of the lifetime of the sensor network. As a result, our experimental results show that the proposed clustering algorithm achieves about $10%{\sim}40%$ performance improvements over the existing clustering algorithms.