• Korean Journal of Environmental Biology
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• v.40 no.3
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• pp.335-340
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• 2022

After detection of red imported fire ant (Solenopsis invicta) at Gamman port in Busan in September of 2017, Animal and Plant Quarantine Agency has surveilled invasive ants in the area with a high invasion risk of ants. However, existing surveillance traps have several limitations such as captured ants could escape easily or it is very hard to set up the trap on a hard ground like concrete or asphalt. To solve these problems, we developed a new trap using multiple narrow tubes to attract ants to the inside of the trap and make it hard for ants to escape. The new trap can be easily set up under various conditions. The new trap has more than four times ant capturing efficacy compared to conventional pitfall traps. Our results confirmed that the new trap could prevent captured ants from escaping. We hope that this newly developed trap would contribute to the prevention of invasive ants.

• Smart Media Journal
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• v.11 no.2
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• pp.70-76
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• 2022

IoT application development using a cloud server causes problems such as data transmission and reception delay, network traffic, and cost for real-time processing support in network connected hardware. To solve this problem, edge cloud-based platforms can use neuromorphic hardware to enable fast data transfer. In this paper, we propose a model optimization method for supporting spiking neural networks on FPGA hardware. We focused on auto-adjusting network model parameters optimized for neuromorphic hardware. The proposed method performs optimization to show higher performance based on user requirements for accuracy. As a result of performance analysis, it satisfies all requirements of accuracy and showed higher performance in terms of expected execution time, unlike the naive method supported by the existing open source framework.

• Journal of Teachers' Pension
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• v.1
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• pp.47-90
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• 2016

사학연금재정재계산위원회(2016)에 의하면 사학연금제도는 2027년에 기금규모가 최고로 도달한 후, 다음 해 부터는 재정수지가 적자로 전환되어 2046년에 기금이 완전히 고갈될 것으로 전망되고 있다. 그래서 동 제도의 지속가능성을 위한 연금재정의 안정화 대책이 시급하다. 현재 상황에서 사학연금제도의 지속가능성에 대한 연구는 자산운용을 효율화하여 기금고갈시점을 최대한 연기하고, 동 기간 공무원연금제도의 개혁과 연계한 지속가능성을 모색하는 방안이 최선의 방안이다. 지금까지 사학연금은 해외투자나 대체투자 등 다양한 자산배분 포토폴리오를 설계 운용하여 왔는데, 대체투자로는 높은 수익률을 실현하여 왔으나 해외투자 수익률은 기대에 미치지 못하였다. 국내외 연기금들 중 지난 6년간 가장 높은 단순 수익률을 실현한 CPPIB의 수익률을 사학연금재정재계산위원회가 사용한 연금재정재계산 수익률에 적용하여 추계한 연금재정은 2044년 기금최고시점에 이르렀고, 2045년부터 재정수지가 음(-)으로 변하여 2060년부터 기금이 완전히 고갈될 것으로 전망되었다. 그리고 사학연금의 운용성과가 미흡한 주식투자 수익률을 국민연금 주식투자 수익률로 적용하였을 경우, 사학연금재정재계산위원회 추계 결과와 비슷한 기금최고시점 및 기금고갈시점을 보였다. 글로벌 경제가 저성장 저금리 기조로 들어서고 있는 이 시점에서, CPPIB가 지난 6년간 실현한 높은 수익률을 중장기에 지속적으로 기대하기는 어렵다. 그래서 사학연금기금을 최대한 유지하기 위해서는 다양한 투자대상을 개발함과 동시에 CPPIB의 자산배분 포토폴리오와 포토폴리오 변동성 및 기대수익률을 통제할 수 있는 수리모형을 도입하고, 국민연금의 주식투자 운용원칙 및 기준을 벤치마킹하여 자산배분을 효율화하여야 한다. 이와 동시에 향후 공무원연금제도 개혁 과정에서 사학연금제도의 지속가능성을 반영할 수 있는 방안에 대한 연구가 필요하다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1A
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• pp.51-58
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• 2008

A cable element happens to vibration easily rather than other elements because a cable element has few rotational stiffness. Dynamic motion of stay cable is distinguished from vibration by wind and/or rain and excitation by support movement. Mostly a stay cable is vibrated by wind and/or rain except that when natural periods coincide between stiffening girder and stay cable. It happens to deterioration of serviceability and durability by vortex shedding, rainy-wind induced vibration, and galloping. Additional damping generated by installation of cable damper is well known good scheme against above phenomena. Researchers have lack of effort to develop the recommendations even if cable stayed bridges are designed and constructed in Korea. Therefore, development of the domestic recommendations should be achieved as soon as possible. This study suggests the consistent and systematic recommendations on vibration controlling design of stay cable by installation of damper. It gives readers two important methodologies that one evaluates required damping ratio, the other determines installing point considering efficiency.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4C
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• pp.229-238
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• 2006

Observed field behaviors are frequently different from the behaviors predicted in the design state due to several uncertainties involved in soil properties, numerical modeling, and error of measuring system even though a sophisticated numerical analysis technique is applied to solve the consolidation behavior of drainage-installed soft deposits. In this study, genetic algorithms are applied to back-analyze the soil properties using the observed behavior of soft clay deposit composed of multi layers that shows complex consolidation characteristics. Utilizing the program, one might be able to appropriately predict the subsequent consolidation behavior from the measured data in an early stage of consolidation of multi layered soft deposits. Example analyses for drainage-installed multi-layered soft deposits are performed to examine the applicability of proposed back-analysis method.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.5C
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• pp.201-208
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• 2010

In this study, the ground settlement was investigated by using monitoring data of the test sites where vacuum consolidation method and surcharge method were applied for improving deep soft soil. The monitoring data are chosen in ${\bigcirc}{\bigcirc}$ area port construction site reclaimed with very soft dredged clay. These data are analyzed to compare the consolidation characteristics between the different loading methods for soil improvement. Through analysis of the loading time, it is shown that the ground settlement reaches its allowable value under vacuum consolidation loading by about 45% faster than that of the surcharge loading consolidation. This could be explained that vacuum consolidation method makes the isotropic consolidation condition so that the time for reaching a certain final preloading without soil failure can be shortened.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.22-24
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• 2022

Recently, Graph Database (GDB) is being used in wide range of industrial fields. GDB is a database system which adopts graph structure for storing the information. GDB handles the information in the form of a graph which consists of vertices and edges. In contrast to the relational database system which requires pre-defined table schema, GDB doesn't need a pre-defined structure for storing data, allowing a very flexible way of thinking about and using the data. With GDB, we can handle a large volume of heavily interconnected data. A network service provider provides its services based on the heavily interconnected communication network facilities. In many cases, their information is hosted in relational database, where it is not easy to process a query that requires recursive graph traversal operation. In this study, we suggest a way to store an example set of interconnected network facilities in GDB, then show how to graph-query them efficiently.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.4
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• pp.57-64
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• 2024

The introduction of Smart Factories has transformed manufacturing towards more objective and efficient line management. However, most companies are not effectively utilizing the vast amount of sensor data collected every second. This study aims to use this data to predict product quality and manage production processes efficiently. Due to security issues, specific sensor data could not be verified, so semiconductor process-related training data from the "SAMSUNG SDS Brightics AI" site was used. Data preprocessing, including removing missing values, outliers, scaling, and feature elimination, was crucial for optimal sensor data. Oversampling was used to balance the imbalanced training dataset. The SVM (rbf) model achieved high performance (Accuracy: 97.07%, GM: 96.61%), surpassing the MLP model implemented by "SAMSUNG SDS Brightics AI". This research can be applied to various topics, such as predicting component lifecycles and process conditions.

• Journal of Advanced Navigation Technology
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• v.28 no.5
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• pp.632-639
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• 2024

In this paper, the analysis method and results of audio data through LVDS interface and data Acquisition of the intercom. Intercom uses LVDS interface to transmit/receive digital audio data between audio interface unit and intercom control panel and to data acquisition of audio signals. Data acquisition using LVDS interface is essential for downloading various audio signals interfaced to the intercom to a PC and performing data analysis on noise, audio qualitys, etc. To achieve this, hardware for audio data acquisition was configured in the intercom test equipment. As a result, individual analysis of intercom input/output audio signals before and after logic processing was possible, which was effective in deriving the cause of noise signals. In addition, by data acquisition on actual voice communication and audio signals in ac system integrated laboratory and an environment/ electromagnetic test, audio signal level measurements and frequency analysis were performed to debug noise signal removal and verify the audio quality of the intercom.

• Korean Journal of Construction Engineering and Management
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• v.9 no.2
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• pp.99-107
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• 2008

Rapidly increasing automobile supply rate according to improved economic level of life makes lack of parking space of apartments. Even though the initial design of parking space compiled with old regulations, it may not observe either new laws or requirement of inhabitants. Even if old apartments have no structural durability problem, outworn facilities and insufficient parking area may be a main reason for reconstruction. It causes waste of national resources and makes recycling issues. Additionally, irregularly parked cars make traffic obstruction to a fire engine and result in many fire accident victims. Parking problems of apartments are not only inconvenience but also serious safety issues. From these points of view, remodeling only for parking area expansion is necessary to avoid overall reconstruction of apartments. The purpose of this study is to suggest a retaining wall selection method for apartments underground parking lots expansion without evacuation of resident people. Effect factors to select retaining wall system are analyzed and weight values are calculated by applying AHP. One selection method of retaining wall is proposed by evaluating applicability and its sensitivity analysis is executed. This selection method is expected to help decision-making of retaining wall system selection.