研究者詳細 - 趙　孟佑

論文 - 趙　孟佑

分割表示643 件中 101 - 120 件目／全件表示 >>

Remote Sensing Applied to the Study of the Triatomines Dispersion Dynamics, Case Study: Indigenous Communities of Paraguayan Chaco 査読有り国際誌

Adolfo Javier Jara Cespedes, Izrael Zenar Casople Bautista, Federico Augusto Gaona Veron, Antonieta Rojas de Arias, Mengu Cho

71st International Astronautical Congress 2020年10月

Sulphur-Fueled Surface Arc Thruster for Propelling Nanosatellites 査読有り国際誌

Senior Shimhanda, Kotaro Hiraka, Taro Inoue, Kazuhiro Toyoda,Mengu Cho

71st International Astronautical Congress 2020年10月

Ionosphere Measurement: Point-to-point Total Electron Content Estimation Using UHF Inter-Satellite Ranging for Cube-Sat Constellation 査読有り国際誌

Hoda Awny El-megharbel, Makiko Kishimoto, Necmi Cihan Örger, Victor Schulz, Tharindu Dayarathna, Rahmi Rahmatillah, Mariko Teramoto, Mengu Cho, Chee Lap Chow, Man Siu Tse and Holden Li,

71st INTERNATIONAL ASTRONAUTICAL CONGRESS 2020 2020年10月

CUBESAT INTERFACE STANDARDIZATION TO ACHIEVE FASTER DELIVERY AND MISSION SUCCESS 査読有り国際誌

Mengu Cho, Takashi Yamauchi, Marloun Sejera, Sangkyun Kim, Hirokazu Masui

71st International Astronautical Congress 2020年10月

SURVEY ON NANO-SATELLITE CAPACITY BUILDING NEEDS AROUND THE WORLD 査読有り国際誌

Mengu Cho, George Maeda, Yasuyuki Miyazaki, Yukihito Kitazawa, Michio Ozawa, Rei Kawashima

71st International Astronautical Congress IAC-20-B4.1.1.x59649 2020年10月

Improvement of Communication System for 1U CubeSat 査読有り国際誌

Makiko Kishimoto, Tharindu Lakmal Dayarathna Malmadayalage, Abhas Maskey, Pooja Lepcha, Dulani Chamika Withanage, Yuta Kakimoto, Yuji Sasaki, Hari Ram Shrestha, BIRDS Partners, George Maeda, Takashi Yamauchi, Sangkyun Kim, Hirokazu Masui, Mengu Cho

34th Annual Small Satellite Conference 2020年08月

CubeSat Electrical Interface Standardization for Faster Delivery and More Mission Success 査読有り国際誌

Mengu Cho, Takashi Yamauchi, Marloun Sejera, Yukihisa Ohtani, Sangkyun Kim, Hirokazu Masui

Small Satellite Conference SSC20-WKI-03 2020年08月

A lean satellite electrical power system with direct energy transfer and bus voltage regulation based on a bi-directional buck converter 査読有り

Juan J. Rojas, Mengu Cho, Yamauchi Takashi

Aerospace 7 ( 7 ) 94 2020年07月

Electrical Propulsion System Using Lunar Regolith Dust as Propellant 査読有り国際誌

Noruji MUTO, Necmi Cihan ORGER, Jose Rodrigo CORDOVA ALARCON, Kazuhiro TOYODA, Mengu CHO

JpGU-AGU Joint Meeting online 2020年07月

Development and Investigation of Communication Issues on a CubeSat-onboard Amateur Radio Payload with APRS Digipeater and Store-and-Forward Capabilities 査読有り

Adrian C. SALCES, Marloun P. SEJERA, Sangkyun KIM, Hirokazu MASUI, Mengu CHO

UNISEC Space Takumi J 9 ( 2 ) 17 - 46 2020年06月

hortening of the Delivery Time for University-Class Lean Satellite 査読有り国際誌

Kiran K. Pradhan, Mengu Cho

Journal of Small Satellites 09 ( 02 ) 2020年06月

Shortening of the Delivery Time for University-Class Lean Satellite 査読有り

Kiran K. Pradhan, Mengu Cho

Journal of Small Satellites 9 ( 1 ) 2020年01月

Survey on nano-satellite capacity building needs around the world 査読有り

Cho M., Maeda G., Miyazaki Y., Kitazawa Y., Ozawa M., Kawashima R.

Proceedings of the International Astronautical Congress, IAC 2020-October 2020年01月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

The ministry of education of Japan (MEXT: Ministry of Education, Culture, Sports, Science and Technology) in 2019 awarded a research commission to Kyutech and UNISEC to investigate many aspects of nano-satellite capacity building around the world; the purpose of this research is to help the Government of Japan formulate its own future plans for this kind of capacity building. This study looked at not only capacity building activities of space faring countries, but also the space development situation (maturity) and their capacity building needs of non-space faring countries/regions. The study covered 52 non-space faring countries/regions in Asia, Middle East, Africa and Latin America. The paper covers the key findings made during the analysis of the survey.

Scopus

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85100929510&origin=inward

Implementation of Adaptive Antenna Array for Ground Station Tracking System 査読有り

MOHAMMAD ZAKI Syazana Basyirah, KAYA Nobuyuki, CHO Mengu

TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN ( 日本航空宇宙学会 ) 18 ( 5 ) 199 - 208 2020年01月

記述言語：英語掲載種別：研究論文（学術雑誌）

<p>As the number of small satellites keeps increasing due to the low-cost development and fast delivery duration, there is a demand for higher capacity and capability of the ground station tracking system. Generally, the existing ground station tracking system faces major performance degradation while tracking satellites because of signals interference and multi-path fading. These problems motivate researchers to come out with interesting solution to mitigate the degradation performance. This paper describes the implementation of adaptive beam forming algorithm of phased array antenna for ground station tracking system. The adaptive antenna array demonstrates electronically self-steering radiation pattern capability towards satellites signals, suppress interferences and multi-path signals. This can be achieved by adapting the Least Mean Square (LMS) algorithm by varying the number and phase of the array antenna elements and the angle of beam steering to determine the Direction of Arrival (DOA) of incoming signals. The performance of adaptive LMS algorithm is investigated in MATLAB software by analyzing the radiation patterns for different number of array antenna elements, phases and beam steering angle. The purpose of LMS algorithm implementation in the Adaptive Array Antenna (AAA) system is to control weights adaptively, optimize the Signal to Noise Ratio (SNR) of the desired signal and minimize the Mean Square Error (MSE).</p>

DOI： 10.2322/tastj.18.199

CiNii Article

CiNii Research

その他リンク： https://ci.nii.ac.jp/naid/130007896457

Cubesat interface standardization to achieve faster delivery and mission success 査読有り

Cho M., Yamauchi T., Sejera M., Kim S., Masui H.

Proceedings of the International Astronautical Congress, IAC 2020-October 2020年01月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

In 2019, a new project to standardize the CubeSat interface started. Discussion has been made utilizing various gathering opportunities of the CubeSat community. A survey on the CubeSat interface has been distributed the CubeSat community to collect the satellite developers' experience and desires regarding the interface, and the CubeSat vendors' reality and desires. A research work to identify the difficulties associated integrating CubeSat components from different vendors is on-going. Initial finding suggests that clear definition of interface related information, especially the digital data communication, in the user manual is really needed. A table of content of the standard has been drafted, which is mainly made of four parts. (1) Interface among components, (2) Interface between CubeSat bus (platform) and mission payloads, (3) Document specification to describe the information related to component interface, (4)Document specification to describe the information related to CubeSat bus (platform) interface. The project aims at submitting a new work item proposal to ISO/TC20/SC14 in summer 2021 and publish the standard by 2024.

Scopus

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85100946371&origin=inward

A grid square statistical approach in data organization for urban growth impact assessment on in-and-outdoor thermal condition in Manila City, Philippines 査読有り

Purio M.A.C., Cho M., Yoshitake T., Renchin T.

Proceedings of the International Astronautical Congress, IAC 2020-October 2020年01月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Urban growth has been observed to be progressively increasing globally as the world's population tends to live in the cities and its surrounding areas. This change, the urban heat emergence for example, affects human living conditions. Results such as thermal discomfort, high prevalence of heat related health conditions, air pollution, increased water usage and energy demand for air conditioning is now receiving more attention. Because of this impact, it is of utmost importance to understand the cause and trends of urban growth in relation to the changes in thermal conditions. Once we understand the relationships between the factors mentioned, it will be possible to predict future trends and therefore assess their impacts before they even happen. This paper provides the use of world grid square statistical approach as a preliminary method in organizing the data to be used in urban growth impact assessment on in-and-outdoor thermal condition in Manila City, Philippines. This approach is aligned with the Japanese national standard for grid-square code (JIS X0410) which is extended for worldwide usage known as the World Grid Square Statistics. It is implemented by dividing the locale into small mesh based on latitudinal and longitudinal line with a fixed partition. With these small meshes representing a small area in the locale, parameters from different range of sources such as land surface temperature from remotely-sensed (satellite imagery), terrestrial data, population, energy consumption and weather data can be merged in the generated mesh grids. This method shall allow easy comparison of area characteristics without being affected by the change of administrative boundaries of towns, municipalities, and districts. In addition, the mesh grid shall serve as a basic boundary unit to provide additional statistical data in the future. Moreover, the proposed system shall allow ease in data linkage and data processing, mapping, data creation in each area, observation area definition and numerical unit in simulation. Once these data are organized in the mesh grids, matrix of values shall be inputs for statistical analysis of data and parametric inputs for predictive models using machine learning methods. Applying the approach in Manila City results to generating 4480 grids with maximum area of 0.02 sq. km and will consequently be populated with data for assessing the impact urban growth on in-and-outdoor thermal condition.

Scopus

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85100946689&origin=inward

Creating cubesat image database for machine learning based onboard classification for future missions 査読有り国際誌

Maskey A., Cho M.

Advances in the Astronautical Sciences 173 475 - 483 2020年01月

担当区分：責任著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

CubeSats have limited downlink capability and can be especially challenging while downlinking images. Onboard selection of images could save bandwidth and time. One method for selection is through machine learning. To train a model, dataset is required. However, no such dataset is publically available. The objective of this study is to create a database specific to CubeSat for on-orbit image classification which can be deployed in future missions. The paper presents three methods for data collection. Firstly, open data from Sentinel 3A is used to create nadir pointed images. Secondly, images from the International Space Station is utilized to create horizon images. Lastly, the dataset is supplemented by Kyushu Institute of Technology’s internal image database from HORYU and BIRDS satellite projects. Data conditioning and augmentation techniques are also provided to extend the dataset resulting into 15,000 images that can be labeled and used for training.

Scopus

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85111867088&origin=inward

Sulphur-fuelled surface arc thruster for propelling nanosatellites 査読有り国際誌

Shimhanda S., Hiraka K., Inoue T., Toyoda K., Cho M.

Proceedings of the International Astronautical Congress, IAC 2020-October 2020年01月

担当区分：責任著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Pulsed electrothermal thrusters use kiloampere discharge currents for polytetrafluoroethylene (PTFE) ablation and sublimation. However, higher arc currents cause higher electromagnetic interference (EMI). A 10 J surface arc thruster (SAT), which adopts current regulating diodes (CRD), was developed that enables significant reduction in EMI. A CRD limits the discharge currents to 5 A in spite of the applied voltage. A low-melting-point sulphur propellant has been used that enables low discharge currents to efficiently ablate it and accelerate it electrothermally. In this paper, the near-term potential for elemental sulphur propellant in SAT is investigated. The advantages of sulphur with respect to PTFE are presented. First, we measured the pulse width of the main discharge. Then sulphur propellant proved superior to PTFE propellant in discharge duration. The mean pulse widths of PTFE and sulphur are 3.38 ms and 22.1 ms, respectively. Secondly, we measured the pressure rise in the vacuum chamber after each discharge. The mean pressure rises of PTFE, sulphur powder and sulphur solid are 0.43 mPa, 0.94 mPa and 1.9 mPa, respectively. Sulphur powder experienced the least intensity of discoloration in comparison with other propellants. The discharge initiator misfired frequently during PTFE ablation, but it ignited successively during sulphur ablation. Experimental results indicate sulphur is a suitable propellant for surface discharge propulsion, and for low arc currents is superior to PTFE.

Scopus

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85100945416&origin=inward

SS27 Radiation protection and monitoring experiment on-board a 1U CubeSat and its ground verification 査読有り国際誌

Murase T., Masui H., Cho M., Wei S.

Proceedings - IEEE International Symposium on Circuits and Systems 2020-October 2020年01月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Commercial-Off-The-Shelf(COTS) Integrated Circuits (ICs) are mostly sensitive to irradiations (e.g., protons, heavy-ions, etc.)in space, leading to various Single-Event Effects (SEEs). Among different SEEs, Single-Event Latch-up (SEL) is one of the most critical because it is detrimental and often damages ICs. This paper reports a circuit implementation that serves to provide protection for COTS ICs from SEL. The on-ground hardware verification on the basis of Californium 252 depicts that the circuit successfully cuts off the SEL current and subsequently resets the COTS IC. The reported circuit has been adopted in a 1U CubeSat that will be launched early 2020.

Scopus

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85109282438&origin=inward

Remote sensing applied to the study of the triatomines dispersion dynamics, case study: Indigenous communities of Paraguayan Chaco 査読有り国際誌

Cespedes A.J.J., Cho M., Bautista I.Z.C., de Arias A.R., Veron F.A.G.

Proceedings of the International Astronautical Congress, IAC 2020-October 2020年01月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

The species distribution models allow finding suitable areas for the development of the disease vectors with a low sampling effort either in time or in costs. The objective of this work is to determine the spatial distribution of triatomines based on the use of entomological and environmental variables using remote sensing tools. To determine the distribution, two main variables have been considered: the environmental variables and the entomological variable (presence of Chagas disease vector in the indigenous communities). For environmental variables were used: mean NDVI, mean temperature, maximum temperature and mean rainfall, all these derived from satellite images. For the entomological variable a total of 110 points of presence of the vector have been taken through manual collect of insects and the use of a real time remote monitoring system for triatomine using traps with sensors wireless networking, this detection information is transmitted to the research centers through internet, which means that its use is limited to areas with cellular coverage. This work also presents a Store-and-forward mission as part of the BIRDS-4 satellite Project of Kyushu Institute of Technology to collect data from remote areas and expand the study area. As a result, a distribution model based on environmental variables has been obtained that predicts the suitable places for the studied triatomines to be present, being able to serve for the ecological and epidemiological surveillance of the indigenous communities at risk, generating early warning systems and serving as a support to the authorities for decision making. Likewise, the environmental variables suitable for the species have been compiled, considering the known points of presence, being able to cite a value of mean temperature around 20 C, a maximum temperature of 32 C, mean precipitation around 10 ml and NDVI values very close to zero, which corresponds to bare terrain or with little vegetation.

Scopus

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85100949172&origin=inward

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