PURPOSES : This study proposes an index for analyzing mobility based on smartcard and taxi data to evaluate imbalances in public transit. METHODS : The proposed mobility index is calculated based on the difference between the mobility indexes of public transit and taxis using the variables of the in-vehicle time, waiting time, and driving ratio. For a more detailed analysis, the distances are divided into short distances, medium distances, and long distances. RESULTS : Public transit mobility indexes are generally evenly distributed, but the taxi mobility indexes are located in the largest legend. When comparing the respective mobilities of public transit and taxis, many areas with a high mobility of taxis (similar to the distribution) exist, especially in the outskirts such as Dobong-gu, Nowon-gu, Gangdong-gu, Guro-gu, Geumcheon-gu, and Eunpyeong-gu. On average, the mobility of public transit according to the distance is smaller in a short distance and higher in a long distance. CONCLUSIONS : The results demonstrate the use of the proposed index for analyzing the basic statuses of complementary indexes for evaluating public transit imbalances. In the future, more detailed results (including socioeconomic variables corresponding to the grid areas) should be studied to identify the impacts of the mobility index.

홀로그램 이미지를 표시할 수 있는 자동차 리어 램프를 제작했다. 홀로그램은 노광할 때 물체 광은 0도, 참조 광은 60도가 되게 광학계를 설계해 투과 타입으로 제작했다. 홀로그램과 광원을 일체형으로 하면서 두께 30mm의 콤팩트 한 재생 장치를 제작했다. 홀로그램 크기는 200×100mm로 제작했다. 에지릿 홀로그램으로 콤팩트 한 재생 장치에 적 용하기 적합했다. 리어 램프는 미등, 정지등, 방향지시등, 후진등과 홀로그램 재생 장치를 포함 시켜 아크릴로 제작했 다. 리어 램프의 외관은 홀로그램 이미지의 의도와 연결되게 배트맨 모양으로 디자인했다. 에지릿 홀로그램을 이용한 콤팩트 한 재생 장치는 리어 램프의 기능과 연계해 사용하기에 적합하다는 것을 확인하였다.

PURPOSES : Recently, increasing number of local governments are introducing on-demand public transportation service in real time to improve the management efficiency of public transportation. In preparation for the autonomous driving era, the “autonomous public transportation mobility on-demand service in real time” is being developed in the public transportation sector to introduce on-demand public transportation. For this service to become the public transportation of the future, it must receive publicity. Therefore, in this study, indicators were selected to evaluate the publicity of the autonomous public transportation mobility on-demand service in real time, and a survey was conducted among the general public to examine the validity of the indicators. METHODS : To secure the publicity of on-demand public transportation in real time, the goal of the service was first set. Second, the keywords of the service were analyzed to define the publicity requirements of this service. Based on the analyzed keywords and definition of publicity, service indicator types were classified, and the indicators were defined by type. A user satisfaction survey was conducted on the final selected indicators to improve the degree of completion of indicator development. The user survey was conducted by presenting selected publicity indicators to respondents responding on a five-point scale to determine whether each indicator could satisfactorily evaluate publicity. RESULTS : When examining various previous research cases and the contents required for autonomous public transportation mobility on-demand service in real time, the required items of publicity indicators were found to be “safety” in terms of “autonomous driving” and “convenience” in terms of “demand response.” Publicity indicators were developed according to these three items. Thirty-one indicators were developed, and a satisfaction survey was conducted on the general public for each indicator. In the survey, most of the indicators scored 3.5 points or higher, indicating that the indicators were generally well defined. Users gave the highest score to “fairness” among the three items, and “reasonable fairness” was found to be a necessary item as a publicity indicator. CONCLUSIONS : In this study, evaluation indicators were selected to secure the publicity of autonomous public transportation mobility on-demand service in real time, and a satisfaction survey was conducted for each indicator. Most of the indicators showed a score of 3.5 or higher, indicating that they were generally well defined. However, this study has a limitation in that it surveys the general population. In future, experts should be included in the survey to increase the degree of completeness of the public indicators.

목적 : 본 연구는 신체장애인을 대상으로 이동 보조기기 사용에 대한 심리적 요인과 환경적 요인이 삶의 만족도에 어떠한 영향을 주는지 분석하고자 한다. 연구방법 : 본 연구는 한국장애인개발원의 장애인삶 패널조사 데이터(2019)를 활용하여 이동 보조기기 이용하는 신체장애 인의 심리적 요인인 장애수용, 우울, 자아존중감과 환경적 요인인 활동제한, 주거환경, 일상생활의 의존성이 삶의 만족도 에 미치는 영향요인을 파악하기 위한 이차자료분석 연구이다. 신체장애인에 대한 일반적 특성은 기술통계와 교차분석을 하였고, 신체장애인의 이동 보조기기 이용 여부에 따른 집단 간의 비교를 위해서 독립표본 t-검정하였다. 신체장애인의 삶의 만족도와 장애수용, 우울, 자아존중감, 활동제한, 주거환경, 일상생활의 의존성 간의 상관관계를 분석하기 위해서 피 어슨 상관분석을 실시하였다. 이동 보조기기를 이용하는 신체장애인의 삶의 만족도에 영향을 주는 요인을 분석하기 위해 서 다중회귀분석을 실시하였다. 또한 현재 사용하고 있는 이동 보조기기의 만족도에 대한 백분율은 그래프로 제시하였다. 결과 :이동 보조기기 사용 여부에 따른 두 집단의 비교에서 심리적 요인, 환경적 요인, 삶의 만족도에서 유의한 차이를 확인하였다. 신체장애인의 삶의 만족도는 장애수용, 자아존중감, 주거환경과 양의 상관관계를 보였으며(p<.01), 우울, 활 동제한, 일상생활의 의존성과 음의 상관관계를 보였다(p<.01). 이동 보조기기를 이용하는 신체장애인의 삶의 만족도에 영 향을 주는 요인은 나이(ß=-.122, p<.001), 장애수용(ß=.263, p<.001), 우울(ß=-.288, p<.001), 활동제한(ß=-.181, p<.001), 주거환경(ß=.102, p<.01)으로 분석되었다. 결론 : 이동 보조기기를 이용하는 신체장애인의 삶의 만족도를 높이기 위해서는 기능에 맞는 이동 보조기기를 선택하고 이에 적응하기 위한 재활프로그램이 활용되어야 할 것이며, 정책적인 지원이 필요할 것이다.

Polycarboxylic ether-based high-range water reducer (PCE) has been proposed to use due to the operational advantages of reduced water content and increased fluidity of cementitious mixtures. But the concern about using PCE can increase the mobility of radionuclides as well. Nuclear Decommissioning Authority (NDA) showed that the PCE formulations increased radionuclide solubility in free solution. Solubility of U(VI), 239Pu, 241Am with the cementitious materials tested with 3:1 pulverized fuel Ash/Ordinary Portland Cement (PFA:OPC) and 9:1 Ground Granulated Blast Furnace Slag/OPC (GGBS:OPC) with PCE that increased at least one and, in some cases, more than three orders of magnitude (between 10-9 and 10-4 mol dm-3) for these radionuclides in the cement-equilibrated solution. It is possible that the relatively low molecular weight substances present in the PCE cement mixture increase the solubility of radionuclides. In addition, the organic substances that are easily miscible with water can contribute to increase the solubility. In this study, several radionuclides (Nb, Ni, Pd, Zr, and Sn) that may be present in intermediate and low-level waste (LIW) repositories were selected based on the half-life and the estimated dose accordingly, and the solubility tests were conducted with and without PCE in solution. To simulate the field condition of the underground repository, synthetic groundwater was prepared based on the recipe by the KAERI Underground Research Tunnel (KURT) DB-3 GW and used as a solvent. The solubility limiting solid phase (SLSP) of each radionuclide was determined using Geochemist’s WorkBench (GWB) model. The selected solid phases are Ni(OH)2, ZrSiO4, Nb2O5, Pd(metal), and SnO2, respectively, and the solubility experiments were conducted with 1.0wt% of PCE per total weight and 0.5 g / 250 ml of selected radionuclide’s SLSP for 90 days at room temperature (25°C). Compared with and without PCE presence in solution, the selected radionuclides also showed an increased solubility with the presence of water reducing agent like PCE. This results can be used to correctly estimate the mobility of target radionuclides with the presence of PCE in repository environments.

Glass wool, the primary material of insulation, is composed of glass fibers and is used to insulate the temperature of steam generators and pipes in nuclear power plants. Glass fiber is widely adopted as a substitute for asbestos classified as a carcinogen. The insulations used in nuclear power plants are classified as radioactive waste and most of the insulation is Very Low-Level Waste (VLLW). It is packaged in a 200 L drum the same as a Dry Active Waste (DAW). In the case of the insulations, it is packaged in a vinyl bag and then charged into the drum for securing additional safety because of the fine particle size of the fiberglass. A safety assessment of the disposal facility should be considered to dispose of radioactive waste. As a result of analyzing overseas Waste Acceptance Criteria (WAC), there is no case that has a separate limitation for glass fiber. Also, in order to confirm that glass fibers can be treated in the same manner as DAW, research related to the diffusion of glass fibers into the environment was conducted in this paper. It was confirmed that the glass fiber was precipitated due to the low flow velocity of groundwater in the Gyeongju radioactive waste repository and did not spread to the surrounding environment due to the effect of the engineering barrier. Therefore, the glass fiber has no special issue and can be treated in the same way as a DAW. In addition, it can be disposed of in the disposal facility by securing sufficient radiological safety as VLLW.

Engineered barriers (concrete and grout) in Low- and Intermediate-Level Waste (L/ILW) disposal facilities tend to degrade by groundwater or rainfall water over a long period of time. During the degradation process, radionuclides stored in the disposal facility might be released into the pore water, which can pass through the natural rock barriers (granite and sedimentary rock) and may reach the near-field and far-field. In this transportation, radionuclide might be sorbed onto the engineered and natural rock barriers. In addition, the organic complexing agent such as ethylenediaminetetraacetic acid (EDTA) and α-isosaccharinic acid (ISA), is also present in pore water, which may affect the sorption and mobility of radionuclide. In this study, the sorption and mobility of 90Sr under different conditions such as two pHs (7 and 13), different initial concentrations of organic complexing agents (from 10-5 M to 10-2 M), and solutions (groundwater, pore water, and rainfall water) were investigated in a batch system. The groundwater was collected at the L/ILW disposal facility located at Gyeongju in South Korea. The pore water and rainfall water were artificially made in the laboratory. The concrete, grout, granite, and sedimentary rock samples were collected from the same study sites from where the groundwater was collected. The rock samples were crushed to 53-150 micrometers and were characterized by XRD, XRF, SEM-EDS, BET, and zeta potential analyzer. 90Sr concentration was determined using liquid scintillation counting. The sorption of 90Sr was described by distribution coefficients (Kd) and sorption reduction factor (SRF). In the case of EDTA, the Kd values of 90Sr remained constant from 10-5 M to 10-3 M and tended to decrease at 10-2 M, while in case of ISA the Kd values decreased steadily as the concentration of ISA was increased from 10-5 M to 10-3 M; However, a sudden reduction in the Kd values were observed above 10-2 M. In comparison to EDTA, ISA gave a higher SRF of 90Sr. Therefore, from the above results, it can be concluded that the presence of ISA has a greater effect on the sorption and mobility of radionuclide in the solutions than EDTA, and the radionuclide may reach near- and far-field of the L/ILW disposal facility.

99Tc is a long-lived radioactive fission product whose mobility in the subsurface is largely governed by its oxidation state. Migration of Tc from a waste repository may be prevented by immobilizing Tc(IV) in durable glass forms. Thus, efficient incorporation and high retention of Tc by glasses is very important for radioactive waste management and environmental remediation. Tc(IV) oxidation to higly volatile Tc(VII) (TcO4 −) at glass vitrification temperatures results in poor Tc retention in the final waste glass. Retention of Tc in the glass is generally improved by reducing conditions since Tc(IV) is not volatile. However, experiments with Tc-magnetite under high temperature and oxic conditions showed re-oxidation of Tc(IV) to volatile pertechnetate. To understand this phenomenon, we employed ab initio molecular dynamics simulations to study structural and electronic properties of Tc-incorporation in magnetite. The study provides the ramification of high temperature on Tc mobilization and changes of Tc retention in magnetite. Theory predictions also indicated enhanced Tc retention in the presence of 1st row transition metal dopants in Tc-incorporated magnetite that was confirmed by experiments. Furthermore, the overwhelming concentration of Cr(VI) co-mingled with Tc(VII) within the secondary waste form where Cr(VI) is more readily reduced than Tc(VII) by reduction potential metrics. Experiments with Tc-magnetite under high temperature and oxic conditions showed re-oxidation of Tc(IV) to volatile pertechnetate. Experiments also showed that magnetite transforms to maghematite resulting in disproportionation and re-oxidation of Tc. This transformation can be suppressed through incorporation of trace elements such as Co, Ni, Zn into magnetite forming spinel. In this talk, I will present results from ab initio molecular dynamics simulations and experiments on the structural and electronic properties of Tc and/or Cr incorporation in magnetite. I will also discuss the temperature effect on Tc/Cr mobilization and changes of Tc/Cr retention in magnetite. In addition, I will discuss the effect of Tc/Cr concentration and 1st row transition metal dopants on their incorporation in magnetite.

The purpose of this paper is to propose part management and standardization to reduce cost and increase compatibility of parts through standardization and standardization of parts to be applied to urban air mobility(UAM) systems, Personnel Air Vehicle(PAV), Vertical Take-Off and Landing (VTOL), and so on. In other words, parts used in the urban air transportation system must be verified from the initial design stage in accordance with the aviation standard, and a systematic management system for various parts must be established to secure stability and improve quality. Therefore, as a system similar to the aviation component management system, it should be thoroughly managed for urban aviation components.

최근 도심항공모빌리티(UAM) 상용화에 앞서 도심 내 항공 교통수단 관련 산업에 대한 연구개발 중요성이 급격히 증가하고 있다. 도심항공모빌리티(UAM) 환경을 조성하기 위해서 핵심 항공 이동 수단 비행체인 개인용 항공기 (PAV) 기체에 관한 연구가 수행되고 있으나, 탑승자 관점의 연구가 상대적으로 부족한 상황이다. 특히 PAV는 탑승 자의 새로운 생활공간으로 활용될 것으로 예상되기 때문에 탑승자의 실내행위를 지원하는 실내공간 설계를 위해서 는 PAV 기체에서 발생하는 물리적 요소가 인체에 미치는 영향에 관한 연구가 필수적으로 이루어져야 한다. 이에 본 연구의 목적은 PAV의 공중 운항 특성으로 인해 인체에 영향을 주는 제약 요소를 도출하고, 이러한 제약 요소가 실내행위를 수행하는 탑승자 인체에 미치는 영향을 파악하는 것이다. 본 연구 결과, 항공 이동 수단 비행 기체 PAV 는 4,000ft 이하에서 운항해야 하는 기준에 따라, 운항고도에 따른 제약 요소는 소음, 진동, 저주파 운동에 의한 멀미 로 나타났다. 이러한 제약 요소가 실내행위에 영향을 미친다는 관점에서 PAV에서 행할 수 있는 실내행위를 자율주 행 자동차, 비행기, PAV 컨셉 사례를 활용하여 도출하고 인체에 미치는 영향과 수준을 고려하여 실내행위 지원을 위한 제약 요소 권장기준을 설정하였다. 또한 실내행위 지원을 위한 제약 요소의 인체 영향 수준을 감소시키기 위해 서는 시트의 형태 및 내장기능(진동 저감 기능, 온도조절, LED조명 등), 개인 좌석별 지향성 스피커를 활용한 외부소 음 감소, 소음과 진동 감소를 위한 내장재 등을 실내공간 설계에 반영해야 함을 제시하였다. 본 연구는 PAV 실내행 위에 영향을 주는 제약 요소를 도출하였고, 인체에 미치는 영향 수준을 확인하였으며, 추후 PAV 실내 설계 시 기초 자료로써 활용할 수 있다는 점에서 의미가 있다.

COVID-19 팬데믹의 장기화는 우리 사회의 많은 것을 변화시켰으며, 특히 감염병 확산 방지를 위한 정책적 개입인 사회적 거리두기는 사회 구성원의 모빌리티 변화를 가져왔다. 본 연구의 목적은 공간적 관점에서 모빌리티에 대한 COVID-19의 차별적 영향을 규명하는 것이다. 이를 위해 서울특별시를 사례로 하여 2019년 대비 2020년의 월별 대중교통 승차 모빌리티 변동률에 대해 공간통계기법을 적용하였고, 다음과 같은 결과를 얻었다. 첫째, 탐색적 공간 데이터 분석 및 군집 분석을 통해 서울에서 COVID-19의 영향이 적었던 2020년 1~2월 이후 서울 중심부에서 모빌리티가 크게 감소하였으며, 점차 모빌리티 변화의 정적인 공간적 자기상관이 증가한 것을 확인하였다. 둘째, 상관분석 및 공간회귀분석을 통하여 모빌리티 변화와 지속적으로 연관되고 영향을 주는 특정 연령, 직업, 소득 변수들을 확인하였다. COVID-19의 확산을 막기 위한 정책적 개입이 모빌리티에 차별적으로 영향을 주었다는 사실은 포스트 코로나 시대에 불평등 완화를 위한 정책 수립의 출발점이 될 것이다.

PURPOSES : In this study, we attempted to derive the optimal operation plan for urban public transportation routes by verifying changes in demand for use according to factors affecting public transportation. METHODS : First, the factors affecting changes in demand for public transportation were drawn. Second, the appropriate areas to be analyzed and their main routes were selected. Third, the basic data required for estimating public transportation traffic demand were collected through transportation card data. Fourth, basic networks and routes in TOVA were established for public transportation assignment. Finally, through traffic assignment, changes in usage demand owing to factors affecting bus routes were verified, and the optical operation plan was derived. RESULTS : Among the three routes selected for analysis, the rearranged B2 route increased by 662 from 6,142 to 6,804 per day, with the largest increase in daily demand. In addition, the number of stops increased with the access time, but there was no change in the average congestion. CONCLUSIONS : Through this study, it is believed that in can be used as the basic data on how to improve bus routes in local governments from the perspective of operators by analyzing the effectiveness of rearranging routes and drawing optimal operation measures.