• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.33-34
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• 2022

The purpose of this study was to provide basic data for applying oyster shells and egg shells as fireproof cladding materials by substituting fine aggregates for oyster shell powder and egg shell powder, and comparing strength and fire resistance performance. The reason for the high strength was thought to be that the oyster shell had higher strength than the egg shell itself, and both ESP and OSP were measured at a backside temperature of less than 500℃, so it was judged that it could be used as a fireproof coating for steel structures.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.70-71
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• 2021

The unit quantity that affects the workability, shrinkage cracking, and durability of concrete is an important factor. Methods for measuring the unit quantity include a high frequency heating method, a capacitance method, a unit volume mass method, and a simple method. However, these methods have the disadvantage of poor measurement method, time required, and precision. To solve this problem, a relatively simple and fast measurement method was adopted to compensate for the shortcomings through a Frequency Domain Reflection (FDR) sensor, and the unit quantity was used. In addition, the measurement data was analyzed by deep learning to evaluate the unit quantity of concrete.

• Korea Trade Review
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• v.46 no.5
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• pp.83-98
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• 2021

This study aims to examine the effects of international trade in intermediate input on the implications of international business cycle properties in Korea. To do this, I have extended standard one goods New Keynesian international business cycle model to incorporate the role of intermediate inputs. After constructing the DSGE model, I have analysed the impulse response function and varian decomposition results. The results show that the model could introduce a new channel, that is, "cost channel" like Eyquem and Kamber (2014). In other words, the model has changed the dynamics of aggregate inflation by the cost channel. When the trade in intermediate goods increase, which is measured by openness of foreign input, the volatility of output, consumption and inflation increase two or three times. However, the model itself fails to explain the full account of cycle behavior of historical data, but the results imply that the trade in intermediate input assumption can help to improve the forecasting ability of international business cycle models.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.8
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• pp.2137-2156
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• 2024

Customer reviews are the second-most reliable source of information, followed by family and friend referrals. However, there are many existing customer reviews. Some online shopping platforms address this issue by ranking customer reviews according to their usefulness. However, we propose an alternative method to rank customer reviews, given that this system is easily manipulable. This study aims to create a ranking model for reviews based on their usefulness by combining product and seller service aspects from customer reviews. This methodology consists of six primary steps: data collection and preprocessing, aspect extraction and sentiment analysis, followed by constructing a regression model using random forest regression, and the review ranking process. The results demonstrate that the ranking model with service considerations outperformed the model without service considerations. This demonstrates the model's superiority in the three tests, which include a comparison of the regression results, the aggregate helpfulness ratio, and the matching score.

• Fisheries and Aquatic Sciences
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• v.27 no.8
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• pp.488-500
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• 2024

The purpose of this research is to analyze the conservation aspects of fishing techniques in small-scale fishing activities in Labuhan Maringgai. The research was conducted from August to November 2022 in Muara Gading Mas village, Labuhan Maringgai, eastern Lampung. The Ecosystem Approach to Fisheries Management (EAFM) was employed as the methodology. The secondary data utilized in this study consisted of fisheries record books and fisheries monitoring reports. The indicator aspects cover 6 domains, namely: Habitat, Fish Resources, Fishing Technology, Social, Economic and Institutional. By employing the EAFM domain value classification, the fisheries management status was determined to be of medium level, with a total aggregate value of 1,204.3. However, the small-scale capture fisheries in Labuhan Maringgai, East Lampung, were categorized as medium status, but with values that tended to be low, particularly in the social domain composite value. This can be attributed to conflicts of interest, compliance levels, and efforts in capacity building.

• International Journal of Highway Engineering
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• v.4 no.2 s.12
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• pp.9-18
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• 2002

The main distresses that influence pavement performance are rutting, fatigue cracking, and longitudinal roughness. Thus, it is important to analyze the factors that affect these three distresses, and to develop prediction models. In this paper, three distress prediction models were developed using DataPave program which stores data from a wide variety of pavement sections In the United States. Also, sensitivity studies were conducted to evaluate how the input variables impact on the distresses. The result of sensitivity study for the prediction model of rutting showed that asphalt content, air void, and optimum moisture content of subgrade were the major factors that affect rutting. The output of sensitivity study for the prediction model of fatigue cracking revealed that asphalt consistency, asphalt content, and air void were the most influential variables. The prediction model of longitudinal roughness indicated asphalt consistency, #200 passing percent of subgrade aggregate, and asphalt content were the factors that affect longitudinal roughness.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.3
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• pp.201-205
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• 2009

This paper addresses issues to efficiently collect and aggregate data of sources within a local and adjacent region in geographic routing for wireless sensor networks. We first introduce the concept of a local sink which collects and aggregates data form source nodes in the region and delivers the aggregated data to a global sink. We also design a model to determine an optimal location of the local sink and propose a mechanism to collect data through the local sink. Simulation results show that the proposed mechanism with the local sink is more efficient in terms of the energy and the data delivery ratio than the existing mechanism without the local sink in a geographic routing.

• Journal of Internet Computing and Services
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• v.10 no.4
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• pp.199-211
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• 2009

Recent advancements in wireless networks have enabled support for mobile applications to transfer data over heterogeneous wireless paths in parallel using data striping technique [2]. Traditionally, high performance data transfer requires tuning of multiple TCP sockets, at sender's end, based on bandwidth delay product (BDP). Moreover, traditional techniques like Automatic TCP Buffer Tuning (ATBT), which balance memory and fulfill network demand, is designed for wired infrastructure assuming single flow on a single socket. Hence, in this paper we propose a buffer tuning technique at senders end designed to ensure high performance data transfer by striping data at transport layer across heterogeneous wireless paths. Our mechanism has the capability to become a resource management system for transport layer connections running on multi-homed mobile host supporting features for wireless link i.e. mobility, bandwidth fluctuations, link level losses. We show that our proposed mechanism performs better than ATBT, in efficiently utilizing memory and achieving aggregate throughput.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.645-648
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• 2016

Cluster based wireless sensor networks have a characteristic that the cluster heads collect and aggregate data from sensor nodes and send data to sink node. In addition, between the adjacent sensor nodes deployed in the same area is characterized to the similar sensing data. In this paper, we propose a transmission algorithm for improving the energy efficiency using these two features in the cluster-based wireless sensor networks. Adjacent neighboring nodes form a pair and the two nodes sense data on shifts for one round. Additionally, two cluster heads are selected in a cluster and one of them alternately collects data from nodes and transmits data to the sink. This paper describes a transmission rounding method and a transmission frame for increasing energy efficiency and compared with conventional methods. We perform computer simulations to evaluate the performance of the proposed algorithm, and show better performance in terms of energy efficiency as compared with the LEACH algorithm.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.3
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• pp.356-360
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• 2010

Recently, there have been many research efforts on privacy-preserving data mining. In privacy-preserving data mining, accuracy preservation of mining results is as important as privacy preservation. Random perturbation privacy-preserving data mining technique is known to well preserve privacy. However, it has a problem that it destroys distance orders among time-series. In this paper, we propose a notion of the noise averaging effect of piecewise aggregate approximation(PAA), which can be preserved the clustering accuracy as high as possible in time-series data clustering. Based on the noise averaging effect, we define the PAA distance in computing distance. And, we show that our PAA distance can alleviate the problem of destroying distance orders in random perturbing time series.