Earticle

플라스틱 종류 중 하나인 폴리스타이렌(PS)은 수환경에서 풍화를 통해 용존성 유기물 (PS-DOM)을 용출하며, 미세플라스틱 오염의 새로운 경로로 주목받고 있다. 특히 PS-DOM은 수환경에서 자외선(UV) 노출과 미생물 활동에 의해 산화 및 자가조립 과정을 겪으며 그 화학적·물리적 특성이 변화할 수 있다. 본 연구는 PS-DOM의 산화 및 조립 특성에서 UV 조사로 인해 나타나는 영향을 확인하고, 그 결과 형성된 조립체의 토양 환경 오염 가능성을 평가하였다. PS-DOM의 조립체 형성은 동적광산란(DLS) 및 크기배제크로마토그래피(SEC)를 통해 분석하였으며, 분해물질의 특성은 GC-MS, 이온 크로마토그래피(IC), NMR 분석을 통해 규명하였다. 그 결과, PS-DOM은 시간 경과에 따라 분자 크기와 분자량이 증가하며 조립체를 형성하였고, UV 조사 및 미생물 활동 은 이러한 변환 과정을 가속화했다. 특히 UV 조사는 산화를 촉진하여 친수성 분해물 질과 친수성 조립체 형성을 심화했으나, 장기간 조사 시에는 조립체의 분해가 관찰되 었다. 이와 같이 UV 조사는 PS-DOM의 거동에 영향을 미치며, 토양 환경 오염을 심화 할 가능성을 나타낸다. 본 연구는 플라스틱 분해물질의 환경 거동 이해에 중요한 기초 자료를 제공하며, 미세플라스틱 오염 연구에서 미세플라스틱 유래 DOM 경로의 중요성을 제시한다.

최근 들어 집회 및 시위가 줄어들고 있지만, 18대 대통령선거를 앞두고 있어서 언제 불법·폭력시위가 발생할지 알 수 없는 상황이다. 따라서 현재와 같은 평온한 시기에 미리 불법·폭력시위진압 방식의 문제점을 차분히 살펴보고 그 대책을 강구해 볼 필요가 있다고 생각한다. 물론 불법·폭력시위는 공공의 안녕질서를 회복하기 위해서 단호하게 대처해야 할 것이다. 그러나 시위진압책임자의 독단이나 시위참가자들의 안전에 대한 고려 없이 무리한 진압방식은 지양되어야 할 것이다. 과거 한국경찰의 불법·폭력시위 진압방식에는 여러 가지 문제점이 있었다고 할 수 있다. 첫째, 상부의 눈치를 보느라고 진압책임자가 독단적·즉흥적으로 진압을 결정하는 것이다. 둘째, 다양한 불법·폭력시위에 대처할 수 있는 훈련된 진압부대가 없다는 것이다. 셋째, 현장지휘 상의 문제이다. 진압방식을 지시한 지방경찰청장이 현장에서 지휘를 하지 않는다는 것이다. 넷째, 불법·폭력시위진압 방식의 문제이다. 불법·폭력시위를 변수 없이 안전하게 진압하기 위해서는,첫째, 불법·폭력시위의 원인을 정확히 파악하여야 할 것이다. 둘째, 불법폭력시위자들의 성향, 시위용품,위험성 등 모든 상황을 면밀히 파악하여야 할 것이다.셋째, 진압방식은 안전을 최우선적으로 고려하여야 할 것이다. 마지막으로 가장 중요한 것은 이러한 의사결정이 진압책임자의 독단이 아니라 관계자들의 충분한 협의에 의하여 합리적으로 결정되어야 할 것이다.

Recently, the assembly and demonstration is decreased. However, it is the situation where it has 18th presidential elections ahead and it cannot know if when illegal and violent demonstration is generated. At this time, we have to take the counterplan on the illegal and violent demonstration suppression method. Of course, the illegal and violent demonstration should be managed conclusively in order to recover the public safety. But the safety of the demonstrators should be secured. In the past, there were many problems in the illegal and violent demonstration suppression method of Korean police. First, the commander determines the suppression dogmatically and extempore. Second, there is not the trained suppression unit to manage the various illegal and violent demonstrations. Third, the district police chief indicating the suppression method does not conduct on the field. Forth, it is the problem of the illegal and violent demonstration suppression method. The demonstration is put down safely to be most important. So, first of all, the cause for the violent demonstration has to be accurately grasped. Second, all situations including the tendency of the illegal violent protesters, demonstration goods, risk, and etc. will have to be carefully checked. Third, the suppression method will have to consider the safety primarily. Finally, the policy decision should not be made by the arbitrary decision of the conductor but it has to be reasonably made by the consultation of the people concerned.

PURPOSES : The first generation of wide base tires introduced in the early 1980s was found to cause a significant increase in pavement damage compared to dual-tire assemblies. However, wide base tires have evolved considerably, and a new generation of wide base tire is thought to be comparable to conventional dual tires for pavement damage. A challenge associated with using wide base tires is the accurate quantification of pavement damage induced by these tires. The objective of this study was to investigate the responses of flexible pavement to continuously moving vehicular loading under various tire configurations. METHODS : The comparison of the strain/stress responses of full-depth pavement caused by conventional dual tire assembly and new generation of wide-base tires was performed. The FE model incorporates linear viscoelasticity of asphalt material and continuous moving load using implicit dynamic analysis. RESULTS AND CONCLUSIONS : The result demonstrates that the new wide-base tires caused slightly more fatigue damage and less primary rutting damage in HMA layer than a dual-tire assembly, but caused more secondary rutting damage in subgrade than a dual tire assembly.

We introduce a new fabrication process for antireflective structured surfaces. A 4-inch silicon wafer was dipped in a suspension of 300-nm-diameter silica particles dispersed in a toluene solution. When the wafer was drawn out of the suspension, a hexagonally packed monolayer structure of particles self-assembled on almost the complete wafer surface. Due to the simple process, this could be applied to micro- and nano-patterning. The self-assembled silica particles worked as a mask for the subsequent reactive ion etching. An array of nanometer-sized pits could be fabricated since the regions that correspond to the small gaps between particles were selectively etched off. As etching progressed, the pits became deeper and combined with neighboring pits due to side-etching to produce an array of cone-like structures. We investigated the effect of etching conditions on antireflection properties, and the optimum shape was a nano-cone with height and spacing of 500 nm and 300 nm, respectively. This nano-structured surface was prepared on a $30\;{\times}\;10-mm$ area. The reflectivity of the surface was reduced 97% for wavelengths in the range 400-700 nm.

Using a virtual assembly tool, engineers are able to design accurate and interference free parts without making physical mock-ups. Instead of a single CAD source, several CAD systems are used to design a complex product in a distributed design environment. In this paper, a multi-CAD assembly method is proposed through an XML and the lightweight CAD file. XML data contains a hierarchy of the multi-CAD assembly. The lightweight CAD file produced from various CAD files through the ACIS kernel and InterOp includes not only mesh and B-Rep data, but also topological data. It is used to visualize CAD data and to verify dimensions of the parts. The developed system is executed on desktop computers. It does not require commercial CAD systems to visualize 3D assembly data. Multi-CAD models have been assembled to verify the effectiveness of the developed DMU system on the Internet.

The dynamic response of the head arm assembly (HAA) of a hard disk drive to an impact load was obtained from a 3D non-linear finite element model using ANSYS/LS-DYNA and from experiments using a modified levitation mass method (LMM). In the finite element model, the impact load was created by modeling the mass as a rigid body and making it collide with the HAA. The velocity, displacement, acceleration, and inertial force of the mass were then obtained from the time history data of the finite element analysis. In the LMM, a mass that was levitated with an aerostatic linear bearing, and hence encountered negligible friction, was made to collide with the actuator arm, resulting in a dynamic bending test for the arm. During the collision, the Doppler frequency shift of the laser beam reflected from the mass was accurately measured with an optical interferometer. The velocity, displacement, acceleration, and inertial force of the mass were accurately calculated from the measured time-varying Doppler frequency shift. A good correlation between the experimental data and FEA results was observed. The FEA was also used to investigate the dynamic response of the HAA to impact by different masses.

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To solve the problems of assembly object variety, volume difference, and texture features not being obvious in the intelligent products assembly process, augmented-reality technology was employed. To improve the feasibility and robustness of the augmented-reality tracking registration algorithm in the product assembly scenarios, combined with the weak texture of product assembly operation objects and the complex scenes, a real-time and robust unmarked tracking registration method was proposed. First, the multimodal approach of LINEMOD was improved to detect the weakly textured assembly target base so that the rough pose of the camera can be obtained and the problem of reinitialization can be solved when the process of tracking registration is interrupted. Then, the iterative closest point (ICP) registration algorithm was improved to accelerate the registration process while accurately positioning the camera pose to determine the benchmark for virtual-real fusion. Finally, based on the pose relationship between the assembly and the assembly guidance information established in the offline phase, visual guidance of the assembly process was realized. A performance analysis and comparison of the proposed tracking registration method show that the proposed method has better accuracy than the LINEMOD template matching method. The visual display of the assembly guidance process shows that the proposed method can be applied to the assembly scene of products lacking texture to realize intelligent assembly.

This work presents the three-dimensional analysis of flow and heat transfer performed for a wire-wrapped fuel assembly of liquid metal reactor using Reynolds-averaged Wavier-Stokes analysis in conjunction with 557 model as a turbulence closure. The whole fuel assembly has been analyzed for one period of the wire-spacer using periodic boundary conditions at inlet and outlet of the calculation domain. Three different assemblies, two 7-pin wire-spacer fuel assemblies and one bare rod bundle, apart from the pressure drop calculations for a 19-pin case, have been analyzed. Individual as well as a comparative analysis of the flow field and heat transfer have been discussed. Also, discussed is the position of hot spots observed in the wire-spacer fuel assembly. The flow field in the subchannels of a bare rod bundle and a wire-spacer fuel assembly is found to be different. A directional temperature gradient is found to exist in the subchannels of a wire-spacer fuel assembly Local Nusselt number in the subchannels of wire-spacer fuel assemblies is found to vary according to the wire-wrap position while in case of bare rod bundle, it's found to be constant.

Background Subacromial pain syndrome (SAPS) is one of the causes of shoulder pain in workers performing repetitive upper extremity movements. However, there have been no studies on physical characteristics such as shoulder total rotational range of motion (ROM) and external to internal rotation muscle strength ratio of workers. Purpose The purpose of this study was to compare the total rotational ROM and external to internal rotation muscle strength ratio in workers with and without SAPS. Study design A cross-sectional study Methods This study included 35 workers with SAPS and 32 workers without SAPS. The total rotational ROM were measured using Smart KEMA motion sensor, and external to internal rotation muscle strength were measured using Smart KEMA pulling sensor. Results The results showed that there were significant differences in the total rotation ROM between the groups (p<0.05). However, no significant difference was found in the external to internal rotation muscle strength ratio (p>0.05). Conclusions Assembly line workers with SAPS had limited total rotational ROM. However, the ratio of external to internal rotation muscle strength ratio was not different for workers without SAPS. These characteristics can be considered factors that should be considered in evaluating workers with SAPS and establishing a treatment plan.

For large facilities having several floors or containers, floor response spectra, FRS, other than ground response spectra need to be developed. However, FRS can have error especially when components are not small in their masses. In this paper, error is estimated in order to specify applicability of the FRS by deriving and comparing with analytic results for two degrees of freedom system. An identity regarding modal vectors and participation factors in the modal method is used to measure the FRS error. It is found that FRS is sufficiently accurate if the mass of a component is one hundredth or less than that of the floor. On the contrary, it is shown that fixed frequency of a component does not affect the FRS accuracy considerably. A compact power plant system consists of two main assemblies with spring mounts is applied as an example for the derivation of the FRS and several aspects associated with its modeling and calculation are discussed.

VTK.js는 의료영상 데이터를 웹 기반으로 가시화하는 라이브러리로 널리 사용된다. 그러나 그 기능이 기존 VTK에 비해 제한적이기 때문에 다양한 기능의 추가 구현을 필요로 한다. 본 논문은 Web Assembly를 활용하여 VTK.js의 기능을 확장하려 한다. 그 예로서 VTK.js에서 지원하지 않는 기법인 환경광 폐색 기법을 Web Assembly로 구현하여 기능을 확장 하였다.

The establishment of emergency medical services and evacuation systems can be said to be part of a direct effort to reduce human damage in disasters and emergencies. In this regard, countries such as the United States, the United Kingdom, and Australia define and utilize the concept of an assembly point from a variety of disaster situations, and domestic discussions on introduction are progressing in stages. There is a lot of discussion regarding the location selection of shelters, but the development of location selection criteria and methodology must be preceded in order to successfully link the function of the assembly point and the establishment of the evacuation facilities including the existing shelters. This study aims to develop a methodology to minimize transfer time by assembling paramedics and local residents to the appointed place in case of an accident. In addition, it aims to develop a technique for physical positioning of the assembly point to achieve this purpose. According to this research objective, the criteria for physical location selection of assembly points were derived, and a methodology for selecting candidate sites was developed to improve emergency medical services in densely populated areas.

This study is to develop a core part Spindle and Nut Spindle of the electronic parking brake system. This demand is the development and launch notification referral order also commissioned state. Domestic competitors company developed and applied to workpiece of Spindle and Nut Spindle. In this study, the market advertisement is aimed over its competitors by developing cost competitiveness and quality stability through parts and components of precision forging engineering. Thus, axle measuring device system is needed to verify the reliability(fastening state of brake system) at the same time the development of Spindle and Nut Spindle. This study is performed to the following four aims. The first is the development of forging process technology for Spindle and Nut Spindle. The second is the development of mold design technology for Spindle and Nut Spindle. The third is the reliability secured technology for axle force(brake system force) of electronic brake system. The last is the development of forging and shape design simulation of Spindle and Nut Spindle.

본 연구에서는 기존 전통적인 방식의 블록 프로그래밍 환경이 갖는 한계점인 기초 로직 중심의 교육, 블록 코딩과 텍스트 코딩의 동시 학습성 한계, 데이터 사이언스 및 인공지능 개발 어려움 등의 한계점을 보완하기 위한 새로운 형태의 파이썬 WASM 기반 블 록 코딩 교육 플랫폼 설계를 제안한다. 제안하는 플랫폼은 웹 기반으로서 학습자가 개발환경을 구축할 필요가 없으며, 작성하는 블 록 로직을 실시간 파이썬 텍스트 코딩으로 변환할 수 있다. 또한, WASM을 활용하여 학습자는 블록 로직을 통해 기초부터 심화, 데 이터 사이언스 및 인공지능 개발까지 다양한 파이썬 로직을 개발할 수 있다. 최종적으로는 제안하는 플랫폼의 구현 결과와 이를 바 탕으로 한 다양한 기능들을 확인한다. 또한, 제안하는 플랫폼을 활용하여 파이썬 기초 로직부터 데이터 시각화, 이미지 처리, 머신 러닝 등의 로직을 블록 코딩으로 구현한다. 이로써 제안하는 플랫폼이 교육적인 목적을 넘어 온전한 파이썬 비쥬얼 블록 코딩 플랫 폼으로서 사용되기에 적합한 구조를 지니고 있는지 검증한다. 본 연구를 통해 학습자는 실제 파이썬과 동일한 환경에서 블록 코딩 과 텍스트 코딩으로 프로그래밍을 학습하며 컴퓨팅적 사고 증진과 실제 파이썬에 대한 이해도를 높일 수 있을 것으로 기대된다. 마 지막으로, 블록 및 텍스트 코딩의 동시 학습을 통하여 추후 학습자의 파이썬 텍스트 환경에 대한 진입 장벽을 낮출 수 있을 것으로 기대된다.

In this research, we propose an architecture of new-type block coding educational platform based on python WASM to redeem the traditional block programming environment's limitation, which are basic logic-centered education, the limitation of simultaneous learning between block coding and text based coding, and difficulty for developing a data science and an artificial intelligence. Learners don't need to set up an development environment as proposed platform is web-based, and this platform can convert block logic written by a learner into python text logic in real time. Futhermore, a learner can develop various python logic from basic to advanced logic, data science and artificial intelligence using block logic operated in WASM. In the last section, we verify the implemented proposed platform and its various functions. In addition, we implement logics such as python basic logic, data visualization, image processing and machine learning using block coding to verify the proposed platform's structure to be used not only as an educational platform but also as a python visual block coding platform. This study is expected to let a learner's computational thinking improve and the understanding of python language both by learning through block and text coding of which in the same environment as real python. Finally, we expect that it can reduce the entry barrier of python text coding environment for a learner by using simultaneous learning between block and text coding.

This study aims to clarify the actual assembly conditions and initial response of school personnel during the 2024 Noto Peninsula Earthquake and to examine implications for future school emergency manuals. The analysis used questionnaire data collected by the Wajima City Board of Education, based on 105 valid responses from school personnel. The results showed that many respondents were themselves severely affected by the disaster. Power outages were experienced by 85 respondents (81.0%), 82 (78.1%) had to evacuate and stay somewhere other than their homes, and 31 (29.6%) reported their houses were half-destroyed or more seriously damaged. Although 78 respondents (74.3%) were aware of the official emergency deployment rule described in the staff action manual, only 1 respondent (1.0%) was able to report to their usual workplace on the day of the earthquake, while 98 (93.3%) were unable to assemble. The main reasons for failing to assemble were disruption of the road network (72 respondents, 68.6%), judgment that travel was too dangerous (71, 67.6%), continuing aftershocks (50, 47.6%), and damage to their own homes (42, 40.0%). These findings indicate that difficulty in reporting to work was caused not by a lack of awareness or commitment, but by overlapping physical, environmental, and family-related constraints. At the same time, even under conditions where assembly was difficult, school personnel still played important initial roles. Fifty respondents (47.6%) engaged in information gathering, 40 (38.1%) in safety confirmation, and 39 (37.1%) in communication and coordination among staff. These findings suggest that school emergency manuals for large-scale disasters should not rely solely on the assumption that all personnel can assemble immediately. Instead, they should specify alternative roles that can be performed even when assembly is impossible, and incorporate communication systems that remain functional under disrupted conditions.