The purpose of this study was to identify and evaluate hazardous road sections based on roadside friction. Using GIS mapping and clustering techniques, this study analyzed traffic accidents and roadside friction data based on latitude and longitude coordinates. The density-based spatial clustering of applications with noise (DBSCAN) algorithm was applied, with parameters of MinPts = 5 and eps = 0.0001, determined through a K-nearest neighbor analysis. The data were separated based on traffic flow direction (uphill/ downhill), and clustering was performed separately in each direction to identify specific hazard zones. The DBSCAN clustering results revealed 18 clusters in traffic accident data and 44 clusters in roadside friction data. Traffic accident clusters include various types of accidents (e.g., vehicle-to-vehicle and vehicle-to-pedestrian accidents), identifying locations as high-accident zones. The clustering results from the roadside friction data highlighted areas with crosswalks, absence of curbs, and roadside parking zones as major risk sections. Future research should analyze the operational design domain (ODD) of autonomous vehicles on hazardous road sections and explore the integration of multiple data sources to establish a comprehensive safety management system for accident prevention in autonomous driving environments. Additionally, road hazard sections are categorized into stages (e.g., hazardous, cautious, and safe) to enhance the precision in assessing road conditions. This categorization, combined with a detailed analysis of ODD, serves as a foundation for future research aimed at improving the safety of autonomous driving environments.
우리나라는 삼면이 바다로 이루어져 있고, 이에 따라 많은 해양 시설로 인한 위험유해물질이 배출되고 있으나, 배출관리 및 규제 시스템이 미비한 상황이다. 따라서, 위험유해물질(HNS) 관리를 위하여 효율적으로 데이터를 수집할 수 있는 시스템이 필요하 다. 본 연구에서는 HNS 데이터를 효율적으로 관리 및 저장하기 위한 데이터 표준화 시스템을 설계하고 이의 표준화 방안을 제시하고 자 한다.
본 연구의 목적은 키워드 네트워크를 활용하여 삶의 질과 거주성 측면에서 국내 농촌지역의 실제 생활 환경을 분석하고 농촌 생활환경의 개선을 위한 정책적 방향성을 제시하는 것이다. 현재 우리나라의 농 촌은 고령화, 인구감소, 경제활동 저하, 기초생활서비스 부족 등의 문제가 발생하고 있다. 이를 해결하 기 위한 농촌 생활환경 개선방안의 연구가 필요하다. 따라서 본 연구에서는 삶의 질(Quality of life)과 거주성(Livability)개념을 바탕으로 이론적 측면에서 국외 연구 동향을 분석하였다. 또한 국내 농촌 생 활환경에 대한 현황을 파악하기 위해 키워드 네트워크 분석을 실시하였다. 이를 토대로 삶의 질과 거주 성 측면에서의 이론적 연구 경향 분석을 통해 실제 우리나라 농촌 생활환경에 직면한 문제점을 분석하 였다. 그 결과 국내에서 농촌 생활환경 개선을 위해 고려해야 할 사항으로 1)녹지 및 생태시설 조성, 2)지 역과 개인 및 주민 간 상호작용 개선, 3)에너지 효율을 고려한 주거공간 마련, 4)다양한 관점에서 농촌환 경을 포괄할 수 있는 목표 설정의 4가지 방안을 제안하였다. 국내 농촌의 개선 목표로 제시되고 있는 지속가능성과 더불어 농촌 회복력(Rural resilience)의 개념을 도입하면 농촌의 기능 회복에 기여할 수 있을 것이다.
This study aims to investigate protein consumption market trends in Korea. Protein consumption was divided according to the protein source into meat, fishery, and plant-based protein. To accomplish the goal of this study, food purchase data from 525 households panels collected by the Rural Development Administration over the last 10 years were used. The results of the study showed an increase or decrease in protein consumption by protein type over the last 10 years, and a reason to explain this change has been suggested. Specifically, this study found a dramatic increase in the consumption of several proteins, including beef sirloin, beef tenderloin, seasoned beef & steak, pork belly, pork shoulder, pork neck, seasoned pork, pork cutlet, sweet and sour pork, canned ham, chicken drumstick, chicken breast, dak gangjeong, Chinese fried chili chicken, salmon, eel, abalone, squid, octopus, webfoot octopus, octopus minor, canned whelk, tofu, cold bean soup,and plant-based milk. Some items showed no increase in consumption (such as beef jerky, pork rib, sausage, bacon, whole raw chicken, cutlass fish, oyster, fish cake, crab stick, surimi sausage,and canned fishery), whereas a few items showed decreased consumption (e.g., mackerel, pollack, cod,and canned tuna)
PURPOSES : This study verifies the stability and uniqueness of the traffic assignment algorithm.
METHODS : The traffic assignment step of the four-phase traffic demand model is an important step in determining the traffic volume of the link in the process of distributing the O/D traffic volume on each link. In this step, primarily, a link-based algorithm based on user equilibrium has been used. The typical link-based algorithm, FWA, is known to provide uniqueness and stability, in theory, regarding traffic assignment results. However, recent studies have raised the controversy that, in reality, the FWA is less stable and unique depending on the termination criterion applied to the FWA in the traffic assignment step. Stability tests and proportionality tests were conducted for the application of algorithms to widely used commercial software (for example, EMME, CUBE, and TransCAD).
RESULTS : According to this study, the uniqueness and stability of the FWA were not followed in the process of actual traffic assignment, unlike the theory.
CONCLUSIONS : The traffic assignment model has essentially the same result when the optimum level is reached, irrespective of the program and traffic allocation techniques used. Therefore, efforts will be required to recognize limitations in practice and to produce stable results at an appropriate level when predicting traffic demand, traffic volume, benefits, and feasibility studies using a traffic allocation model.
본 연구는 백두대간 지리산권역 내 훼손지의 유형을 분류하고, 각 훼손 유형별 실태조사를 통해 훼손 정도를 파악하여 훼손지의 복원 방향을 제시하기 위한 기초자료로 활용하기 위해 수행되었다. 지리산권역의 훼손실태를 분석한 결과 전체 훼손지의 패치 수는 57개로 확인되었고, 평균고도가 낮고 경사가 완만한 지역일수록 훼손지의 패치 수 및 훼손 면적이 더 넓게 나타났다. 훼손 유형은 초지(폐경지)와 경작지의 비율이 높게 나타나 농업적 토지이용이 주요 훼손 요인으로 분석되었 다. 이 중 14개소의 훼손지를 대상으로 실태조사를 수행한 결과, 훼손 유형은 초지, 경작지, 복원지, 벌채지 및 나지로 분류되었 다. 각 유형별 교란정도(일년초 및 이년초의 비율, 도시화지수, 교란율)를 분석한 결과, 초지 및 경작지에서는 대부분 초본류로 만 구성된 1층 구조의 단순한 식생구조와 교란정도가 높게 나타났다. 소나무 유묘가 다수 식재된 복원지의 경우 2층 구조의 식생구조가 나타났고, 복원사업으로 인한 교란과 인근의 등산로로 인해 귀화식물의 유입이 다른 훼손지에 비해 특히 높게 나타났다. 나지의 경우 고도가 높아 귀화식물의 유입은 낮았지만, 일년초와 이년초의 비율이 높게 나타나 조사된 모든 유형의 훼손지는 천이 초기단계로 판단되었다. 훼손 유형별 군락을 서열화한 결과, Ⅰ축상의 복원지, 경작지, 초지, 벌채지 및 나지 순으로 나타나 훼손 유형별로 구분되어 배열되는 경향을 보였다. 또한 훼손 유형별 조사지와 참조생태계의 군락을 서열화한 결과, 종조성의 차이를 확인할 수 있었다. 이처럼 생태적 복원 절차에 따라 식생정보에 기초한 훼손 유형별 실태를 진단하고, 진단 결과와 함께 참조생태계와의 종조성의 차이를 확인함으로써 향후 복원 목표 및 복원 방향 설정의 기초자료로 활용하고자 한다.
Metal-organic frameworks (MOFs) are of significant interest because of their high porosity, which facilitates their utilization in gas storage and catalysis. To enhance their current properties in these applications, it is necessary to elucidate the interactions between molecules in a confined environment that differ from those in bulk conditions. Herein, we study the confined molecular interaction by investigating the solvent-dependent photophysical properties of two different-sized molecules inside MOF-5. Ruthenium tris-bipyridine (Rubpy) and coumarin 153 (C153) are encapsulated in MOF-5. Rubpy with MOF-5 (Rubpy@MOF) is prepared by building MOF-5 around it, resulting in limited space for solvent molecules in the pores. The smaller C153 is encapsulated in the preformed MOF-5 (C153@MOF) by simply soaking the MOF in a concentrated C153 solution. C153@MOF permits more space for solvent molecules in the pore. Their characteristic absorption and emission spectra are examined to elucidate the confined molecular interactions. Rubpy@MOF and C153@MOF exhibit different spectral shifts compared to the guest molecules under bulk conditions. This discrepancy is attributed to the different micro-environments inside the pores, derived from confined host-guest interactions in the interplay of solvent molecules.
In this study, the effect of tempering on the stretch-flangeability is investigated in 980 MPa grade dual-phase steel consisting of ferrite and martensite phases. During tempering at 300 oC, the strength of ferrite increases due to the pinning of dislocations by carbon atoms released from martensite, while martensite is softened as a consequence of a reduction in its carbon super-saturation. This strength variation results in a considerable increase in yield strength of the steel, without loss of tensile strength. The hole expansion test shows that steel tempered for 20 min (T20 steel) exhibits a higher hole expansion ratio than that of steel without tempering (T0 steel). In T0 steel, severe plastic localization in ferrite causes easy pore formation at the ferrite-martensite interface and subsequent brittle crack propagation through the highly deformed ferrite area during hole expansion testing; this propagation is mainly attributed to the large difference in hardness between ferrite and martensite. When the difference in hardness is not so large (T20 steel), on the other hand, tempered martensite can be considerably deformed together with ferrite, thereby delaying pore formation and hindering crack propagation by crack blunting. Eventually, these different deformation and fracture behaviors contribute to the superior stretch-flangeability of T20 steel.