In order to reduce environmental pollution, it is necessary to increase the recycling rate of waste. For this, the separation of recyclables is of utmost importance. The paper conducted a study to automatically discriminate containers by material for beverage containers among recyclables. We developed an algorithm that automatically recognizes containers by four materials: metal, glass, plastic, and paper by measuring the vibration signal generated when the beverage container collides with the bottom plate of the collection box. The amplitude distribution, time series information, and frequency information of the vibration signal were used to extract the characteristics indicating the characteristic difference of the vibration signal for each material, and a classifier was developed through machine learning using these characteristics.

본 논문에서는 BIM을 활용한 흙막이 시스템을 개발하고 소개한다. 선행 연구 분석을 통해서 흙막이 BIM 시스템을 이루는 기술들 에 대한 조사를 바탕으로 요소 기술들을 개발하였다. 첫 번째 요소 기술로, 선행 연구 및 표준 등을 활용해 BIM라이브러리를 구축하여 범용성과 재사용성을 확보하였다. 두 번째로, 토공 2D 기반의 토공 물량 산출법들을 분석하고 흙막이 BIM 시스템으로 활용하되 추가 로 IDW 보간법을 활용하여 지형 생성 및 토공량 산출 시스템을 구축하였다. 세 번째로, 물량 산출을 위한 4가지 수식을 제안하여 객체 마다 각각 다르게 물량 산출법을 적용하여 개발하였다. 이후, 시스템에서 산출되는 물량산출서와 2D 기반 물량산출서와의 비교와 검 증을 통해서 시스템이 앞으로 나아가야할 방향과 한계에 대해 알아보았다.

There are a number of methods to evaluate the quality of squid. However, when purchasing the fish, consumers and retails rely only on the sensory test and flavor in the field. Therefore, this study was aimed to prove relationship between scientific indicator and sensory test. Total viable cell count (TVC), viable cell count of Pseudomonas spp., pH and volatile basic nitrogen (VBN) were selected as scientific indicators and mesured during the storage of squid at different temperature. The squid was storaged at 3 different temperature (5oC, 15oC, 20oC). Off flavor determination time was measured by R-index, and kinetic modeling was conducted. Activation energies of offflavor determination time, TVC, Pseudomonas spp, VBN, and pH were 51.210 kJ/mol, 42.88 kJ/mol, 50.283 kJ/mol, 72.594 kJ/mol and 41.99 kJ/mol respectively. Activation energy of off-flavor determination time was approximated to viable cell count of Pseudomonas spp., TVC, pH and VBN as an order. Especially, viable cell count of Pseudomonas spp. had best match of the activation energy. Therefore, it was judged that indicator of off-flavor determine time was viable cell count of Pseudomonas spp..

In this study, a drop analysis of metallic disposal containers for radioactive wastes is performed according to accident scenarios at the disposal site. The weight of the disposal container is about 8 tons, and the ingot-type wastes are loaded in the disposal container. To simulate the floor of the disposal site as the impact target, the reinforced concrete pad is modeled. High impact energy of the disposal container due to their heavy weight and high drop height causes excessive deformation and failure of the concrete target having relatively weak strength. Dynamic growth of cracks due to such failures causes penetration and delamination of concrete. Since the impact force delivered to the container strongly depends on the failure of the concrete pad, it is important to properly simulate the failure of the concrete in the drop analysis. A material erosion method can be used to simulate the concrete failure. In the case of applying erosion based on the finite element method (FEM), the element is deleted when the element exceeds a certain criterion, which causes material and energy loss problem. To solve this problem, mesh-free methods such as smoothed particle hydrodynamics (SPH) can be commonly used, but the mesh-free method has the disadvantage of incurring high numerical cost. Therefore, an adaptive method combining SPH and FEM-based SOLID elements is used for concrete target modeling to simulate excessive deformation and failure of the concrete target. In the adaptive coupling method of SPH and SOLID, the concrete target is first modeled as a solid element. When the damage of concrete exceeds the failure criterion, the solid element is eroded and the SPH element replacing the solid element is activated. Since the activated SPH element continues to participate in the impact, the problem of loss of materials and energy can be effectively solved. In this way, analysis results consistent with actual physical phenomena can be obtained.

Interest in the rammed construction method using eco-friendly materials is increasing in modern architecture. However, the work of construction is not convenient and will require a lot of manpower and time. This study proposes an automation compactor consisting of a compactor frame, crank arm, servo motor, wire, and a compactor hammer. The compactor hammer is fixed on the wire to achieve up-down movement by servo motor. And the state of up-down movement of the proposed compactor in 4 steps was had a dynamic analyzed. Through the actual compression experiment, the reliability of the proposed compactor is verified and is expected to be used in rammed earth construction.

본 연구에서는 기존의 네이버후드 효과 연구가 가지는 방법론적 이슈를 고려한 실증적인 방법을 적용하여, 학생들의 학업성 취도에 대한 네이버후드 효과를 규명하고자 하였다. 연구 목적의 달성을 위하여 개인-학교-네이버후드 3수준의 다수준 모형 분석을 수행하였다. 분석의 결과는 다음과 같다. 첫째, 기초모형을 통해 학생들의 수능 점수에 대한 수준별 영향력을 확인한 결과, 개인, 학교, 네이버후드 순으로 높은 영향을 미치는 것으로 나타났다. 네이버후드 효과의 정도는 과목별로 다소간의 차이가 있었는데, 국어에 비해 영어 점수에 대한 네이버후드 효과가 더 높게 나타났다. 둘째, 모형 3을 통해 지역별 네이버후드 효과를 살펴본 결과, 대부분의 지역에서 이전 모형에 비해 네이버후드 효과의 정도가 감소하였다. 그러나 양천구, 강남구 등 일부 학교군에 서는 여전히 높은 네이버후드 효과가 존재하는 것으로 나타났다. 본 연구는 그동안 논쟁이 되어왔던 네이버후드 효과에 대해 실증적인 분석을 통해 정량적인 수치를 제시하였다는 데에 의의가 있다. 이러한 결과는 학업성취도의 공간적 격차와 관련하여 교육정책의 방향을 결정하는 데에도 도움이 될 것으로 기대된다