• International Journal of Fuzzy Logic and Intelligent Systems
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• 제12권4호
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• pp.263-269
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• 2012

The ability to characterize feature objects from radar readings is often limited by simply looking at their still frame reflectivity, differential reflectivity and differential phase data. In many cases, time-series study of these objects' reflectivity profile is required to properly characterize features objects of interest. This paper introduces a novel technique to automatically track multiple 3D radar structures in C,S-band in real-time using Doppler radar and profile their characteristic reflectivity distribution in time series. The extraction of reflectivity profile from different radar cluster structures is done in three stages: 1. static frame (zone-linkage) clustering, 2. dynamic frame (evolution-linkage) clustering and 3. characterization of clusters through time series profile of reflectivity distribution. The two clustering schemes proposed here are applied on composite multi-layers CAPPI (Constant Altitude Plan Position Indicator) radar data which covers altitude range of 0.25 to 10 km and an area spanning over hundreds of thousands $km^2$. Discrete numerical simulations show the validity of the proposed technique and that fast and accurate profiling of time series reflectivity distribution for deformable 3D radar structures is achievable.

• 소성∙가공
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• 제25권3호
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• pp.195-202
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• 2016

Direct laser melting(DLM) is an additive manufacturing process that can produce parts by solidification of molten metallic powder layer by layer. The properties of the fabricated parts strongly depend on characteristics of the metallic powder. Atomized powders having spherical morphology have commonly been used for DLM. Mechanical ball-milling is a powder processing technique that can provide non-spherical solid powders without melting. The aim of the current study was to investigate the effect of powder morphologies on the deposition quality in DLM. To characterize the morphological effect, the performances of spherical and non-spherical powders were compared using both single- and multi-track DLM experiments. DLM experiments were performed with various laser process parameters such as laser power and scan rate, and the deposition quality was evaluated. The surface roughness, cross-section bead shape and process defects such as balling or non-filled area were compared and discussed in this study.

• 한국소음진동공학회논문집
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• 제19권6호
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• pp.614-619
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• 2009

The STW(servo track writing) system which is the process of writing servo signals on disks before assembling in drives uses the spindle motor-chuck mechanism to realize low cost because the spindle motor-chuck mechanism has merit which can simultaneously write multi-disk by piling up disks in hub. Therefore, when the spindle motor-chuck mechanism of horizontal type operates in high rotation speed it is necessary to reduce the effect of RRO(repeatable run-out) and NRRO(non-repeatable run-out) to achieve the high precision accuracy of nano-meter level during the STW process. In this paper, we analyzed that the slip in assembly surfaces can be caused by the mechanical tolerance and clamping force in hub-chuck mechanism and can affect NRRO performance. We designed springs for centering and clamping considering centrifugal force by the rotation speed and assembly condition. The experimental result showed NRRO performance improves about 30 % than case of weak clamping force. The result shows that the optimal design of the spindle motor-chuck mechanism can effectively reduce the effect of NRRO and RRO in STW process.

• 한국자동차공학회논문집
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• 제3권2호
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• pp.16-29
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• 1995

In this study a tracked vehicle is idealized as a 2-dimensional 9-degrees-of-freedom model which takes into account the effects of HSU units, torsion bars, and track. For the model equations of motion are derived using Kane's method. By using the equations of motion, a numerical example is solved and results are compared to those obtained by using a general purpose multi body dynamic analysis program. The comparison study shows the reasonable coherence between the two results. which confirms the effectiveness of the model. With the model, dynamic response optimization is carried out. The objective function is the peak value of the vertical acceleration of the vehicle at the driver's seat, and the constraints are the wheel travel limits, the ground clearance. and the limits of other design variables. Three different sets of design variables are chosen and used for the optimization. The results show the attenuation of the acceleration peak value. Thus the procedure presented in this study can be utilized for the design improvement of the real system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권10호
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• pp.5161-5178
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• 2019

Correlation Filter was recently demonstrated to have good characteristics in the field of video object tracking. The advantages of Correlation Filter based trackers are reflected in the high accuracy and robustness it provides while maintaining a high speed. However, there are still some necessary improvements that should be made. First, most trackers cannot handle multi-scale problems. To solve this problem, our algorithm combines position estimation with scale estimation. The difference from the traditional method in regard to the scale estimation is that, the proposed method can track the scale of the object more quickly and effective. Additionally, in the feature extraction module, the feature representation of traditional algorithms is relatively simple, and furthermore, the tracking performance is easily affected in complex scenarios. In this paper, we design a novel and powerful feature that can significantly improve the tracking performance. Finally, traditional trackers often suffer from model drift, which is caused by occlusion and other complex scenarios. We introduce a relocation component to detect object at other locations such as the secondary peak of the response map. It partly alleviates the model drift problem.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권11호
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• pp.5436-5458
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• 2017

Automatic Video Surveillance System (AVSS) has become important to computer vision researchers as crime has increased in the twenty-first century. As a new branch of AVSS, baggage detection has a wide area of security applications. Some of them are, detecting baggage in baggage restricted super shop, detecting unclaimed baggage in public space etc. However, in this paper, a detection & classification framework of baggage is proposed. Initially, background subtraction is performed instead of sliding window approach to speed up the system and HSI model is used to deal with different illumination conditions. Then, a model is introduced to overcome shadow effect. Then, occlusion of objects is detected using proposed mirroring algorithm to track individual objects. Extraction of rotational signal descriptor (SP-RSD-HOG) with support plane from Region of Interest (ROI) add rotation invariance nature in HOG. Finally, dynamic human body parameter setting approach enables the system to detect & classify single or multiple pieces of carried baggage even if some portions of human are absent. In baggage detection, a strong classifier is generated by boosting similarity measure based multi layer Support Vector Machine (SVM)s into HOG based SVM. This boosting technique has been used to deal with various texture patterns of baggage. Experimental results have discovered the system satisfactorily accurate and faster comparative to other alternatives.

• 한국디지털정책학회:학술대회논문집
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• 한국디지털정책학회 2007년도 춘계학술대회
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• pp.33-40
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• 2007

The Customs Administration, unlike other administrative service, should respond to constantly changing external environment. The Customs has to actively adapt itself to government policy changes, economic changes and international environment changes to facilitate the flow of trade logistics and maintain trading relations wi th other countries. The purpose of this paper is to explain policy directions of the Korea Customs Service which enforces various policies related to tariff and non-tariff barrier elimination for the trade liberalization while the Korean government is pursuing FTAs on a multi-track basis. This paper aims to seek ways to apply FTA policies to the Korean society and economy in a smooth manner. First of all, this paper examines changes in Customs administration brought by the proliferation of FTAs to such areas as FTA negotiations, import/export management, duties and taxes collection, drawback reduction/exempt ion of duty application area of preferential tariff rate and country of origin management. Then, the paper sets FTA missions of "supporting Customs Administration to lead the new trend of free trade environment" after analyzing the environment changes. To achieve the FTA mission mentioned above, the KCS designated 4 strategies and 40 implementation tasks. The 4 strategies are named "4C Strategies" taking initial letters from Client-oriented, Customized procedures, Cooperation and Constitution. "4C" also refers to Foresee(strategies to foresee the successful establishment of FTA policies) or For C(Customer or Customs). The KCS will continue to create new tasks through various channels and monitor their implementation process, and to help FTA regime successfully take root in Korea.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.1505-1510
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• 2008

A railway is a complex system integrated with a lot of technical elements such as trains, track facilities, human factors, operation & control and maintenance. As a mass transportation system, a railway could contain potential risks that may result in a high death rate and property losses. Accordingly, Railroad Safety Technology R&D Corps. is adopting the plan of the construction of Railway Safety Test Facilities as a part of the Railway Total Safety Project to enhance the railway safety, and carrying out researches on effective project management methods with Systems Engineering techniques. Recently, various systems engineering tools such as CORE or Cradle are applied to manage the system requirements and the project management process in the part of the aerospace engineering and automobile engineering so on. The railway industry also makes an effort to develop an efficient management skills using systems engineering tools as the railway system is multi-disciplinary. Therefore, we propose the more effectual management method of constructing the Railway Safety Test Facilities applying the systems engineering tool to the research.

• Asian Journal of Business Environment
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• 제6권2호
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• pp.27-32
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• 2016

Purpose - This paper aims to analyze and investigate to find out the appropriate ways to make an easy TBT of smart city. It is an important issue between Korea and China because TBT of smart city has lots of advantages in IT, S/W, IOT, and Home network. Research design, data and methodology - First, the paper made use of reviewing2nd data analysis and focused on group interview, and then compared with analysis on the international rule and system such as smart city system, technical regulation, and standard through test certification procedure and inspection. Second, this paper reviewed electric/electronic test, certification, and calibration. Third, through analyzing MRA between Korea and china, the paper focused on SDoC, Mutual Acceptance of International certification, and IECCB scheme. Results - Through the comparison and analysis, this paper found that it is important to promote multi-track agreements with the countries that need short-term promotion. Moreover, it is necessary to conclude an agreement with the leading countries in Middle East and Central America. Conclusions - Through the above the reviews and analysis, we can see the importance of promotion in FTA and MRA with the efforts to remove the obstacles and promote to make an easy TBT by MRA between Korea and China.

• Imaging Science in Dentistry
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• 제46권2호
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• pp.141-144
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• 2016

The aim of this report is to present two cases of canalis basilaris medianus as identified on cone-beam computed tomography (CBCT) in the base of the skull. The CBCT data sets were sent for radiographic consultation. In both cases, multi-planar views revealed an osseous defect in the base of the skull in the clivus region, the sagittal view showed a unilateral, well-defined, non-corticated, track-like low-attenuation osseous defect in the clivus. The appearance of the defect was highly reminiscent of a fracture of the clivus. The borders of osseous defect were smooth, and no other radiographic signs suggestive of osteolytic destructive processes were noted. Based on the overall radiographic examination, a radiographic impression of canalis basilaris medianus was made. Canalis basilaris medianus is a rare anatomical variant and is generally observed on the clivus. Due to its potential association with meningitis, it should be recognized and reported to avoid potential complications.