• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.697-702
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• 2017

A preliminary study was carried out to investigate the feasibility of replacing honeycomb cores with pyramidal truss cores in the doors of urban transit railway vehicles. The doors in current operation are sandwich structures comprising a honeycomb core and reinforcements between two facesheets. The structural requirements of doors for urban transit vehicle are specified in the KRS and KRT and standards, according to which the deflections from three-point bending tests must be limited. To this end, two types of pyramidal truss cores with equivalent mass to a honeycomb core were designed. The structural stiffness of doors with pyramidal truss cores and honeycomb cores were numerically calculated via finite element analysis. The three-point bending models were constructed and simulated, and then the calculated deflections were compared with the requirements specified in the regulations. The results show that doors with pyramidal truss cores satisfied the stiffness requirements, although their deflections were 2.5% larger than that of the honeycomb cores. Therefore, the pyramidal truss cores could replace the aluminum honeycomb cores, and their multi-functional capability could be exploited.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.672-679
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• 2018

This paper describes a methodology for shape design using an optimal design system, whereas generally a three dimensional analysis is required for such designs. An automatic finite element mesh generation technique, which is based on fuzzy knowledge processing and computational geometry techniques, is incorporated into the system, together with a commercial FE analysis code and a commercial solid modeler. Also, with the aid of multilayer neural networks, the present system allows us to automatically obtain a design window, in which a number of satisfactory design solutions exist in a multi-dimensional design parameter space. The developed optimal design system is successfully applied to evaluate the structures that are used. This study used a stress gauge to measure the maximum stress affecting the parts of the side housing bracket which are most vulnerable to cracking. Thereafter, we used a tool to interpret the maximum stress value, while maintaining the same stress as that exerted on the spot. Furthermore, a stress analysis was performed with the typical shape maintained intact, SM490 used for the material and the minimizing weight safety coefficient set to 3, while keeping the maximum stress the same as or smaller than the allowable stress. In this paper, a side housing bracket with a comparably simple structure for 36 tons was optimized, however if the method developed in this study were applied to side housing brackets of different classes (tons), their quality would be greatly improved.

• International Journal of Highway Engineering
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• v.6 no.4 s.22
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• pp.13-24
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• 2004

The Marshall mix design method used in Korea, which was described in the design & construction regulation, had been introduced from Japan Highway Cooperation standard guide. Most engineers have thought that it is the major reason that causes pavement distresses. Therefore, there is a need to modify the current Marshall mix design through using the volumetric design concept, which is most widely used in asphalt mix design. The modified mix design determines the preliminary optimum asphalt content at 4% VTM (Voids in Total Mix). If the Marshall properties, which are VFA, VMA, stability, and flow, were satisfied with the requirements, the preliminary optimum asphalt content is determined as the final optimum asphalt content. The modified Marshall mix design considers VMA. while the current Marshall mix design does not consider VMA. By considering the Marshall stability and flow as the criteria instead of design factors, the modified Marshall mix design is able to decrease the errors occurred in Marshall stability test The test was performed to compare the Marshall properties between current and modified Marshall mix design. The left results showed that there was no difference in the Marshall properties, except for VTM. Thus, the modified Marshall mix design can produce the asphalt mixtures with the constant VTM (4%), and it can improve the asphalt mixture quality in Korea.

• Journal of Food Hygiene and Safety
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• v.24 no.1
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• pp.86-93
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• 2009

This study was conducted to determine microbiological assessment on edible ices, which is one of mandatory items for HACCP application, and to provide basic scientific data for the improvement of HACCP system. In HACCP applied edible ice companies, the contamination levels of total counts, yeast and mold, and coliform from raw materials, mixed samples before sterilization, mixed samples after sterilization, and final products of edible ices were lower than those of non-HACCP applied edible ice companies. Foodborne pathogens, such as L. monocytogenes, Salmonella spp., B. cereus, B. aureus, Y. enterocolitica were not detected in all samples of edible ices from HACCP applied edible ice companies, but S. aureus was isolated1 from 1 raw material, 1 mixed samples before sterilization and 1 final product of edible ices from non-HACCP applied edible ice companies, respectively.

• Proceedings of the International Union of Geodesy And Geophysics Korea Journal of Geophysical Research Conference
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• 2003.05a
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• pp.17-17
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• 2003

한반도에 있어서의 지진의 영향을 분석하기 위해서는 강지진동 연구가 필수적이다. 강지진동 자료가 부족한 한반도의 특성상 모사를 통해 연구하고 있다. 강지진동 분석을 하기 위해서는 되도록 노이즈가 포함되어 있지 않은 지진파자료를 선택하여 그 지진자료의 스펙트럼 분석을 통해 감쇠상수 k, Q 등을 구한다. 이러한 감쇠상수 값을 통해 한반도의 진동 특성을 이해할 수 있다. 그러나 감쇠상수를 구하는 과정에서 감쇠상수 분석에 사용된 지진자료에 노이즈가 더해졌을 경우, 어떤 형태로 스펙트럼 영역에 영향을 미치고, 감쇠상수에는 어떤 영향을 미치는 지를 연구하여 노이즈효과를 제거할 수 있는 최적화된 분석에 관한 연구가 선행되어야 한다고 본다. 따라서 이번 연구에서는 강지진동 모사프로그램을 가지고 노이즈효과를 적용하면서 감쇠상수에 노이즈가 어떤 영향을 미치는 지에 대한 수치 해석적 연구를 실시하였다. 합성지진파에 이 합성지진파와 전혀 다른 주파수 형태를 보이는 노이즈를 강도를 달리하면서 합성해 본 결과, 노이즈효과를 고려할 수 있는 몇 가지 요소가 있음을 알 수 있었다. 감쇠상수 k값을 강지진동 모사프로그램으로부터 값을 달리하며 합성해 본 결과 노이즈효과를 보이는 것을 알 수 있었으며, 감쇠상수 k를 선형회귀를 통해 $k_{s}$ 와 $k_{q}$를 구할 때의 적용 주파수 범위를 변화시켰을 때도 일정한 양상의 노이즈 효과를 보였다. 또 지진자료와 노이즈를 중첩시킨 지진파 시계열 자료의 정부분만을 감쇠상수 k를 구하는 선형회귀에 이용했을 경우에도 노이즈 효과를 보였다. 또한 계산되어 나온 감쇠상수 값으로부터 특정지역의 지반운동의 특성을 이해할 수 있는 스펙트럼 가속도, 최대 가속도, 및 최대속도 값에 따른 감쇠식을 구하였다. 이것을 한반도와 같은 판 내부 환경인 ENA 값과 비교하였으며 기존의 연구와도 비교하였다.심으로부터 지오이드까지의 거리, 지오이드로부터 지표까지의 거리를 정의해주었으며, 각 격자점의 수직구조를 정의하기 위해 깊이에 따른 각 매질의 밀도, P파의 속도, S파의 속도, P파에 대한 Q값, S파에 대한 Q값을 정의 해주었다. S파의 속도를 구하기 위해서 지구 내부 물질을 포아송 매질이라는 가정 하에, 관계식을 $Vp{\;}={\;}SQRT(3){\;}{\times}{\;}Vs$ 이용하였다. 획득한 모델치들을 이용해 동해와 동해 인근 지역에 대한 초기모델을 구축하였다. 약 1 × 10/sup 6/ e/sup -//sec·n㎡ 의 전자선량에 해당되며 이를 기준으로 각각의 illumination angle에 대한 임계전자선량을 평가할 수 있었다. 실질적으로 Cibbsite와 같은 무기수화물의 직접가열실험 시 전자빔 조사에 의해 야기되는 상전이 영향을 배제하고 실험을 수행하려면 illumination angle 0.2mrad (Dose rate : 8000 e/sup -//sec·n㎡)이하로 관찰하고 기록되어야 함을 본 자료로부터 알 수 있었다.운동횟수에 의한 영향으로써 운동시간을 1일 6시간으로 설정하여, 운동횟수를 결정하기 위하여 오전, 오후에 각 3시간씩 운동시키는 방법과 오전부터 6시간동안 운동시키는 두 방법을 이용하여 품질을 비교하였다. 각 조건에 따라 운동시킨 참돔의 수분함량을 나타낸 것으로, 2회(오전 3시간, 오후 3시간)에 나누어서 운동시키기 위한 육의 수분함량은 73.37±2.02%를 나타냈으며, 1회(6시간 운동)운동시키기 위한 육은 71.74±1.66%을 나타내었다. 각각의 운동조건에서 양식된 참돔은 사육초기에는 큰 변화가 없었으나, 사육 5일 이후에는 수분함량이 증가하여 15일에는 76.40±0.14, 75.62±0.98%의 수분함량을 2회와 1회 운동시킨 참돔의 육에서 각각 나타났다. 운동횟수에 따른 지

• Journal of KIISE:Software and Applications
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• v.31 no.5
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• pp.677-696
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• 2004

Component-based software engineering (CBSE) composes reusable components and develops applications with the components. CBSE is admitted to be a new paradigm that reduces the costs and times to develop software systems. The high quality of component designs can be assured if the consistency and correctness among the elements of a component are verified with formal specifications. Current formal languages for components include only some parts of contracts between interfaces, structural aspects and behavioral aspects of component, component-based system, component composition and variability. Therefore, it is not adequate to use current formal languages in all steps of a component design process. In this paper, we suggest a formal language to specify component designs Component-Z. Component-Z extends Object-Z, adds new notations to specify components. It can be possible to specify interfaces, the inner structure of a component, inner workflows, and workflows among interfaces with Component-Z. In addition, Component-Z provides the notations and semantics to specify variability with variation points, variants and required interfaces. The relation between interfaces and components is defined with mapping schemas. Parallel operator is used to specify component composition. It can be possible to describe deployed components with the specifications of component-based systems. Therefore, the formal specification language proposed in this paper can represent all elements to design components. In the case study, we specify an account management system in a bank so that we show that Component-Z can be used in all steps of component design.

• KIPS Transactions on Software and Data Engineering
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• v.10 no.10
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• pp.391-398
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• 2021

Since the leased line is a structure that exclusively uses two connected areas for data transmission, a stable quality level and security are ensured, and despite the rapid increase in the number of switched lines, it is a line method that is continuously used a lot in companies. However, because the cost is relatively high, one of the important roles of the network operator in the enterprise is to maintain the optimal state by properly arranging and utilizing the resources of the network leased line. In other words, in order to properly support business service requirements, it is essential to properly manage bandwidth resources of leased lines from the viewpoint of data transmission, and properly predicting and managing leased line usage becomes a key factor. Therefore, in this study, various prediction models were applied and performance was evaluated based on the actual usage rate data of leased lines used in corporate networks. In general, the performance of each prediction was measured and compared by applying the smoothing model and ARIMA model, which are widely used as statistical methods, and the representative models of deep learning based on artificial neural networks, which are being studied a lot these days. In addition, based on the experimental results, we proposed the items to be considered in order for each model to achieve good performance for prediction from the viewpoint of effective operation of leased line resources.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.8
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• pp.570-578
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• 2019

In this era of big data, a variety of government organizations are trying to create new added value via Information Integration. Therefore, several projects related to government agencies' information sharing have activated system connection/integration. The risk factors of system operation, however, have increased as the volume of Information Integration System grows. The interference in information sharing is predicted to affect the operation of the agencies, and the issue will grow even worse with massive impact on civil society when the agency operation is interrupted due to system failures in terms of infrastructure, software, data quality, and security. Diverse studies related to the maintenance of Information System have been conducted, but there is currently no evaluation framework for the operational system of Information Integration between various government agencies. In this respect, this study distinguishes each of the Information System components, Data, IT, People, Process, systematizes with Plan-Do-See, and finally presents a maturity model for Information Integration. Nine derived processes were analyzed through interview and questionnaires from Information Integration System officials, further suggesting maturity stage applying CMMI. This model allows diagnosis of the maturity level of an Information Integration System, and is expected to be utilized as resource for improving organizational processes.

• Tunnel and Underground Space
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• v.32 no.6
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• pp.435-450
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• 2022

In step-by-step site selection for geological disposal of high-level radioactive waste, parameters necessary for site selection will be acquired through deep drilling surveys from the basic survey stage. Unlike site investigations of rock mass structures such as tunnels and underground oil storage facilities, those related to the geological disposal of high-level radioactive waste are not only conducted in relatively deep depths, but also require a high level of quality control. In this report, based on the 750 m depth drilling experience conducted to acquire the parameters necessary for deep geological disposal, the methodology for deep drilling and the geology, geophysics, geochemistry, hydrogeology and rock mechanics obtained before, during, and after deep drilling are discussed. The procedures for multidisciplinary geoscientific investigations were briefly described. Regarding in-situ stress, one of the key evaluation parameter in the field of rock engineering, foreign and domestic cases related to the geological disposal of high-level radioactive waste were presented, and variations with depth were presented, and matters to be considered or agonized in acquiring evaluation parameters were mentioned.

• Journal of the Korean Geotechnical Society
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• v.40 no.1
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• pp.5-14
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• 2024

PHC piles demonstrate superior resistance to compression and bending moments, and their factory-based production enhances quality assurance and management processes. Despite these advantages that have resulted in widespread use in civil engineering and construction projects, the design process frequently relies on empirical formulas or N-values to estimate the soil-pile friction, which is crucial for bearing capacity, and this reliance underscores a significant lack of experimental validation. In addition, environmental factors, e.g., the pH levels in groundwater and the effects of seawater, are commonly not considered. Thus, this study investigates the influence of vibrating machine foundations on PHC pile models in consideration of the effects of varying pH conditions. Concrete model piles were subjected to a one-month conditioning period in different pH environments (acidic, neutral, and alkaline) and under the influence of seawater. Subsequent repeated direct shear tests were performed on the pile-soil interface, and the disturbed state concept was employed to derive parameters that effectively quantify the dynamic behavior of this interface. The results revealed a descending order of shear stress in neutral, acidic, and alkaline conditions, with the pH-influenced samples exhibiting a more pronounced reduction in shear stress than those affected by seawater.