Model-Based Engineering Education with Practical Activities Using HEPTA-Sat

In this study, we designed and implemented an education using CubeSat educational kit “HEPTA-Sat” to acquire Model-Based Systems Engineering (MBSE) practically. We share the lessons learned there. In the development of complicated systems such as CubeSat, it is difficult to manage requirements and tasks only in the mind, and omissions and inconsistencies may occur. And, in communication between members and document accumulated in the project, there is often a contradiction with the receiver, since there is implicit information which is not clarified in the background. Therefore, by describing a system in a modeling language and managing it by connecting various related information, it is possible to grasp the whole complicated system and its context, and to succeed project management and knowledge management. Therefore, we designed a course to practically acquire approach to realize the above system development and conducted it. The course consisted of overview of Systems Engineering, practical assembly of HEPTA-Sat, explanation of the system model, practical training in mission design and modeling, mission implementation and verification, and presentations. Because modeling is a highly abstract task that describes the structure and behavior of a system graphically, it is difficult for beginners. For this reason, students will practice assembling the HEPTA-Sat, which enables them to learn the basic functions of the satellite system, before handling the system in an abstract manner, and deepen their understanding of the specific system. In modeling, free graphic drawing tool diagrams.net is used, the system is expressed from 3 views (operational, functional, physical), and 2 sides of static and dynamic. A series of flow is presented so that modeling can be performed while maintaining consistency among multiple models. In addition, an example of the mission and system model of HEPTA-Sat was prepared, and it was used to promote the understanding modeling approach. Mission design, modeling, implementation and verification were carried out as a field of the practice of the learned content. Verification Matrix which arranged the verification item by the retrieval from the model and the report which records the result of the verification were also made. They are connected to model by hyperlink as the simple demonstration of connecting model and context. Because it was possible to teach consistently with one thing, positive opinions such as It was easy to understand by dealing with the system from both abstract and concrete aspects. were obtained from the participants. In the last presentation, many students were able to deepen their understanding of the model. Therefore, if the cycle from input to output can be carried out multiple times, it is expected that understanding will improve

End-to-End Joint Target and Non-Target Speakers ASR

This paper proposes a novel automatic speech recognition (ASR) system that can transcribe individual speaker's speech while identifying whether they are target or non-target speakers from multi-talker overlapped speech. Target-speaker ASR systems are a promising way to only transcribe a target speaker's speech by enrolling the target speaker's information. However, in conversational ASR applications, transcribing both the target speaker's speech and non-target speakers' ones is often required to understand interactive information. To naturally consider both target and non-target speakers in a single ASR model, our idea is to extend autoregressive modeling-based multi-talker ASR systems to utilize the enrollment speech of the target speaker. Our proposed ASR is performed by recursively generating both textual tokens and tokens that represent target or non-target speakers. Our experiments demonstrate the effectiveness of our proposed method.Comment: Accepted at Interspeech 202

Diminished neutralizing activity against the XBB1.5 strain in 55.9% of individuals post 6 months COVID-19 mRNA booster vaccination: insights from a pseudovirus assay on 1,353 participants in the Fukushima vaccination community survey, Japan

This study investigates the neutralizing activity against the XBB1.5 variant and the ancestral strain in a population post-bivalent vaccination using a pseudo virus assay validated with authentic virus assay. While bivalent booster vaccination and past infections enhanced neutralization against the XBB 1.5 strain, individuals with comorbidities showed reduced responses. The study suggests the need for continuous vaccine updates to address emerging SARS-CoV-2 variants and highlights the importance of monitoring real-world immune responses

DECIGO pathfinder

DECIGO pathfinder (DPF) is a milestone satellite mission for DECIGO (DECi-hertz Interferometer Gravitational wave Observatory) which is a future space gravitational wave antenna. DECIGO is expected to provide us fruitful insights into the universe, in particular about dark energy, a formation mechanism of supermassive black holes, and the inflation of the universe. Since DECIGO will be an extremely large mission which will formed by three drag-free spacecraft with 1000m separation, it is significant to gain the technical feasibility of DECIGO before its planned launch in 2024. Thus, we are planning to launch two milestone missions: DPF and pre-DECIGO. The conceptual design and current status of the first milestone mission, DPF, are reviewed in this article

The status of DECIGO

DECIGO (DECi-hertz Interferometer Gravitational wave Observatory) is the planned Japanese space gravitational wave antenna, aiming to detect gravitational waves from astrophysically and cosmologically significant sources mainly between 0.1 Hz and 10 Hz and thus to open a new window for gravitational wave astronomy and for the universe. DECIGO will consists of three drag-free spacecraft arranged in an equilateral triangle with 1000 km arm lengths whose relative displacements are measured by a differential Fabry-Perot interferometer, and four units of triangular Fabry-Perot interferometers are arranged on heliocentric orbit around the sun. DECIGO is vary ambitious mission, we plan to launch DECIGO in era of 2030s after precursor satellite mission, B-DECIGO. B-DECIGO is essentially smaller version of DECIGO: B-DECIGO consists of three spacecraft arranged in an triangle with 100 km arm lengths orbiting 2000 km above the surface of the earth. It is hoped that the launch date will be late 2020s for the present

Development of Sustainable Evolutionary Space Human Resource Training Program Using HEPTA-Sat

In recently year, although it is expected that the market of space industry will be higher in the future, there is shortage of human resources in the space field. Such as CubeSat Project, OJT type education, although it can gain knowledges which suit its area, it has some problem which is not to be able to conduct to multiple people, to take a long time and not to get a global understanding about the system. In addition, many tacit knowledges, which are gained through experience so far, may be lost without being inherited to next generation because it was not be formalized. In this paper, in order to solve these problems and develop human resources, we developed an education program. It extracts and inherits tacit knowledge at the same time in a classroom which composed of instructors, students, and teaching materials, and makes it possible to understand nano/microsatellite system engineering. And we clarified its usefulness from the results of the implementation at home and abroad

HEPTA-Sat Training Program: International Knowledge Transfer Using Hands-on Type CubeSat Education

HEPTA-Sat Training Program offers an international knowledge transfer network consisting HEPTA-Sat Training Kit, HEPTA-Sat instructors (university faculties) and students with appropriate knowledge sharing methods. The uniqueness of this proposal is 1) decomposition of nano-satellite education and visualization of major architecture. 2) It presents a learning process using hardware and software called kit and text for each visualized item. In this paper, we introduce a hands-on type knowledge transfer program using HEPTA-Sat Training Kit in which university faculties and teaching assistants visit universities or high schools, or inviting participants, and teach the fundamentals of space engineering through the assembly, testing and integration of the Training Kit. This visiting class is available for technical/science/managerial education as the first step on the nano-satellite development

Mechanism of Cuticle Hole Development in Human Hair Due to UV-Radiation Exposure

Hair is easily damaged by ultraviolet (UV) radiation, bleaching agents or permanent wave treatments, and as damage progresses, hair loses its gloss, develops split ends and breaks. However, the causes of hair damage due to UV radiation have not yet been clarified. We discovered that in one mechanism facilitating damage to wet hair by UV radiation, the unsaturated fatty acids in wet hair produce hydroxy radicals upon exposure to UV radiation, and these radicals produce cuticle holes between the cuticle layers. In wet hair exposed to UV radiation, cuticle holes were produced only between the cuticle layers, whereas when human hair was immersed in a solution containing hydroxy radicals produced by Fenton’s reaction, a random production of cuticle holes was noted. It is thought that hydroxy radicals are produced only between the cuticle layers by exposure to UV radiation, and cuticle holes are formed only in this region because one of the polyunsaturated fatty acids, linoleic acid, with a bis-allyl hydrogen, is found between the cuticle layers