1,720,982 research outputs found
Installing a molecular truss beam stabilizes MOF structures
No full textEnhancing the stability and durability of metal-organic frameworks (MOFs) is vital for practical applications because many promising MOF materials suffer from phase transitions and/or structural decompositions with humidity being a particularly damaging condition. In mechanical engineering, the frame of buildings and furniture can be stabilized significantly by installing a truss beam. Employing the same principle, we functionalized the organic component of MOF-5 to contain a carbazole moiety that can act as a molecular truss beam by reaching across the corner and forming a stable pi-pi interaction with a phenyl group on the edge position of the MOF-skeleton. This structural support enhanced the stability of the MOF substantially, allowing the designed MOF to maintain compositional integrity under steam conditions at 90 degrees C for similar to 5 days. The unmodified MOF-5 shows clear signs of structural collapse after similar to 1 h.11Nsciescopu
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
UGV 효과성 및 운용적합성 측정을 위한 시험평가 방안
Full text link학위논문(석사) -- 서울대학교대학원 : 공과대학 기계공학부, 2023. 2. 이경수.최근 육군은 자율주행 기술을 육군의 무기체계 및 수송체계에 도입하기 위한 연구를 진행하고 있다. 육군의 훈련 및 전시 상황은 대부분 비포장 도로로 이루어져 있어 자율주행 기술을 도입하기 위해서는 일반 도심환경과 다른 상황에서의 성능 변화를 검토해야 한다. 비포장 도로 주행에 따라 차량의 진동으로 인해 차량에 장착된 센서의 인지 능력이 저하되는 예시가 존재한다. 따라서 자율주행 기술의 도입을 위해 육군 특성에 맞는 시나리오를 정의하고, 자율주행 차량의 운용 적합성을 평가할 수 있어야 한다.
본 논문은 육군의 차량의 운용 환경에서 자율주행 차량의 운용 적합성을 평가하기 위한 시험 시나리오와 평가 지표를 개발하였다. 시험 시나리오는 페가수스 프로젝트의 6-레이어 포맷을 참조하여 제안하였다. 페가수스 프로젝트의 정의와 육군 사고사례를 소개하고 이를 바탕으로 시나리오를 개발하였다. 시나리오는 추상 수준에 따라 Functional Scenario, Logical Scenario, Concrete Scenario로 구분하여 작성하였다. 제안한 시나리오에 주행도로의 노면 특성을 포함하여, 육군 운용 환경을 반영하도록 하였다. 운용적합성 평가를 위해서 자율주행 차량의 주행 안전성, 승차감 및 자율주행 성능을 평가하고자 하였다. 안전성 평가 항목은 횡 방향 오착, 횡 방향 가속도, 종 방향 가속도, 각 바퀴 별 연직 방향 힘으로 제시하였다. 승차감은 연직 방향 가속도로 확인하였고, 자율주행 성능은 조향각으로 확인하였다.
개발한 시나리오에 대해 구성한 시뮬레이션 환경에서 자율주행 차량을 테스트하여 제시한 평가 항목에 대한 성능을 검토하였다. 시뮬레이션 환경은 TruckSim 소프트웨어와 MATLAB을 이용하여 구축하였다. 구축한 시뮬레이션 환경에서 시나리오 별 테스트를 통해 자율주행 차량의 주행 안전성, 승차감 및 자율주행 성능을 확인하였다. 특히, 제안한 시나리오 중 비포장도로 곡선 경로를 고속으로 주행하는 경우 차선 유지 성능이 악화됨을 확인하였으며, 제안한 시나리오의 필요성을 알 수 있었다. 제안한 시험 시나리오와 평가 지표는 대한민국 육군의 자율주행 차량의 무기 체계 및 수송 체계에 도입할 때 운용 적합성을 증대하는 데에 기여하고, 수송 안전 예규 작성 시에도 참고할 수 있을 것으로 예상된다.In recent years, the Korean Army has been actively carrying out research to adopt autonomous driving technology into their weapons and transportation systems. A key point to note is that most training and actual war-time scenarios require mobility in unpaved and off-road scenarios, hence there is a need to assess the performance of autonomous driving systems in such situations. As an example, severe vibrations arising from these unpaved roads may result in the degradation in performance of on-board perception sensors. Therefore, scenarios that fit the environmental characteristics of the Korean Army need to be defined in order to accurately assess the applicability of autonomous vehicles.
This paper presents a series of test scenarios and evaluation metrics to evaluate the applicability of autonomous driving systems for the Korean Army. The scenarios were developed based on the 6-Layer format adopted from the Pegasus Project, in conjunction with various accident cases from the Korean Army. Depending on their level of abstraction, the scenarios were categorized into three types: Functional, Logical and Concrete Scenarios. Within these scenarios, specific traits regarding the road surface were also included to more accurately represent the use-cases within the Korean Army. As a measure for performance, the vehicles stability, ride comfort, and autonomous driving capabilities were evaluated using the following metrics. For stability, lateral error, lateral acceleration, longitudinal acceleration and the vertical force on each wheel were used. For ride comfort, vertical acceleration of the vehicle was utilized. Finally for the autonomous driving capabilities, the steering wheel angle was observed.
Furthermore, a simulation environment was developed in TruckSim and MATLAB to assess the aforementioned performance measures of autonomous vehicles. Simulation results have shown a significant degradation in lane-keeping abilities for high-speed, unpaved, curved roads, further reinstating the need for such scenarios.
The proposed scenarios and evaluation metrics are expected to play a significant role in improving the applicability of autonomous vehicles into the Korean Armys weapons and transport systems, as well as provide a framework for transport safety regulations in the near future.Abstract i
Table of Contents iii
Chapter 1. Introduction 1
1.1. Research Motivation 1
1.2. Previous Research 4
1.3. Thesis Objective and Outline 6
Chapter 2. Scenario Background 8
2.1. Pegausu Project Scenarios 8
2.2. Accident Cases 12
Chapter 3. Scenario Configurations 15
3.1. Functional Scenarios 15
3.2. Logical Scenarios 20
3.3. Concrete Scenarios 25
Chapter 4. Simulation Environment 34
4.1. Designing the Simulation Environment 34
4.1.1. Roughness 35
4.1.2. Frictional Coefficient 37
4.1.3. Road Frequency 37
4.1.4. Simulation Ego Vehicle 38
4.2. Metrics for evaluation applicability 40
Chapter 5. Simluation Results and Discussion 42
5.1. GS-U-N 42
5.2. TR-U-N 46
5.3. GS-U-SO 50
5.4. GS-U-DO 54
Chapter 6. Conclusion 58
Bibliography 61
국문 초록 64석
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Controlling π–π Interactions of Highly Soluble Naphthalene Diimide Derivatives for Neutral pH Aqueous Redox Flow Batteries
No full textOrganic redox-active molecules are a promising platform for designing sustainable, cheap, and safe charge carriers for redox flow batteries. However, radical formation during the electron-transfer process causes severe side reactions and reduces cyclability. This problem is mitigated by using naphthalene diimide (NDI) molecules and regulating their π–π interactions. The long-range π-stacking of NDI molecules, which leads to precipitation, is disrupted by tethering four ammonium functionalities, and the solubility approaches 1.5 m in water. The gentle π–π interactions induce clustering and disassembling of the NDI molecules during the two-electron transfer processes. When the radical anion forms, the antiferromagnetic coupling develops tetramer and dimer and nullifies the radical character. In addition, short-range-order NDI clusters at 1 m concentration are not precipitated but inhibit crossover. They are disassembled in the subsequent electron-transfer process, and the negatively charged NDI core strongly interacts with ammonium groups. These behaviors afford excellent RFB performance, demonstrating 98% capacity retention for 500 cycles at 25 mA cm-2 and 99.5% Coulombic efficiency with 2 m electron storage capacity. © 2023 Wiley-VCH GmbH.11Nsciescopu
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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