A proposal of TCP congestion control for LEO Satellite Network taking into account handover problem

Tsunoda, Hiroshi,Ohta, Kohei,Kato, Nei,Nemoto, Yoshiaki 통신위성우주산업연구회 2000 Joint Conference on Satellite Communications Vol.2000 No.-

Recently, much research attention has been focused on LEO satellite networks connected to ISL(Inter Satellite Link). A global network, covering the whole earth, can be developed if wireless and wired networks are seamlessly connected by TCP/IP protocol. However, being originally designed for wired networks, the implementation of TCP/IP on LEO satellite networks may give rise to some difficulties, such as dynamic propagation delay caused by handover and re-routing. In this paper, we propose enhanced TCP congestion control mechanism for LEO satellite network. Our proposal aims to attenuate handover problem with the use of IP header's TTL field. Our simulation results show how effective our mechanism is avoiding unnecessary fast retransmit and decreasing congestion.

Feasibility of Societal Model for Securing Internet of Things

( Hiroshi Tsunoda ),( Rodrigo Roman ),( Javier Lopez ),( Glenn Mansfield Keeni ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.8

In the Internet of Things (IoT) concept, devices communicate autonomously with applications in the Internet. A significant aspect of IoT that makes it stand apart from present-day networked devices and applications is a) the very large number of devices, produced by diverse makers and used by an even more diverse group of users; b) the applications residing and functioning in what were very private sanctums of life e.g. the car, home, and the people themselves. Since these diverse devices require high-level security, an operational model for an IoT system is required, which has built-in security. We have proposed the societal model as a simple operational model. The basic concept of the model is borrowed from human society - there will be infants, the weak and the handicapped who need to be protected by guardians. This natural security mechanism works very well for IoT networks which seem to have inherently weak security mechanisms. In this paper, we discuss the requirements of the societal model and examine its feasibility by doing a proof-of-concept implementation.

Development of a WLAN Based Monitoring System for Group Activity Measurement in Real-Time

Hiroshi Tsunoda,Hidehisa Nakayama,Kohei Ohta,Akihiro Suzuki,Hiroki Nishiyama,Ryoichi Nagatomi,Kazuo Hashimoto,Yuji Waizumi,Glenn Mansfield Keeni,Yoshiaki Nemoto 한국통신학회 2011 Journal of communications and networks Vol.13 No.2

In recent years, there has been a rise in epidemiological evidence suggesting the health benefits of a physically active lifestyle. However, it is not always easy for individuals to personally recognize the optimal conditions for exercise and physical activity. Wearable acceleration-based pedometers have become widely used in estimating the amount of physical activity, and to a limited extent,providing information regarding exercise intensity, but they have never been used to assess adaptation to exercise. In order to realize simultaneous activity monitoring for multiple users exercising outdoors, we developed a prototype wireless local area network (WLAN) based system. In our system, a WLAN is deployed outside, and a user wearing a smart phone and monitoring device exercises freely within the coverage area of the wireless network. By doing so, the developed system is able to monitor the activity of each user andmeasures various parameters including those related to exercise adaptation. In a demonstration experiment, the developed system was evaluated and used to monitor users enjoying a Nordic walk, after which users were immediately able to receive their exercise report. In this paper, we discuss the requirements and issues in developing an activity monitoring system and report the findings we obtained through the demonstration experiment.

Development of a WLAN Based Monitoring System for Group Activity Measurement in Real-Time

Tsunoda, Hiroshi,Nakayama, Hidehisa,Ohta, Kohei,Suzuki, Akihiro,Nishiyama, Hiroki,Nagatomi, Ryoichi,Hashimoto, Kazuo,Waizumi, Yuji,Keeni, Glenn Mansfield,Nemoto, Yoshiaki The Korea Institute of Information and Commucation 2011 Journal of communications and networks Vol.13 No.2

In recent years, there has been a rise in epidemiological evidence suggesting the health benefits of a physically active lifestyle. However, it is not always easy for individuals to personally recognize the optimal conditions for exercise and physical activity. Wearable acceleration-based pedometers have become widely used in estimating the amount of physical activity, and to a limited extent, providing information regarding exercise intensity, but they have never been used to assess adaptation to exercise. In order to realize simultaneous activity monitoring for multiple users exercising outdoors, we developed a prototype wireless local area network (WLAN) based system. In our system, a WLAN is deployed outside, and a user wearing a smart phone and monitoring device exercises freely within the coverage area of the wireless network. By doing so, the developed system is able to monitor the activity of each user andmeasures various parameters including those related to exercise adaptation. In a demonstration experiment, the developed system was evaluated and used to monitor users enjoying a Nordic walk, after which users were immediately able to receive their exercise report. In this paper, we discuss the requirements and issues in developing an activity monitoring system and report the findings we obtained through the demonstration experiment.

Factors Predicting the Presence of Concomitant Enterocele and Rectocele in Female Patients With External Rectal Prolapse

Akira Tsunoda,Tomoko Takahashi,Kenji Sato,Hiroshi Kusanagi 대한대장항문학회 2021 Annals of Coloproctolgy Vol.37 No.4

Purpose: External rectal prolapse (ERP) is frequently associated with other pelvic disorders, such as enterocele, rectocele, and perineal descent. Evacuation proctography makes it possible to visualize the development of such anatomical abnormalities. The aim of this study was to identify the variables that would predict associated abnormalities in patients with ERP.Methods: Between February 2010 and August 2019, 124 female patients with ERP, who were evaluated using proctography were included in this study. Enterocele was diagnosed when the extension of the loop of the small bowel was located between the vagina and rectum. A significant rectocele was defined as >20 mm in diameter. Multivariate analysis was used to establish which morphological parameters best predicted the presence of enterocele or rectocele.Results: Sixty-five patients had ERP alone, while 59 patients (47.6%) had additional findings on proctography. The most frequently associated abnormality was enterocele with 48 of the patients (38.7%) having this condition. Rectocele was detected in 17 of the 124 patients (13.7%). The median length of the ERP was 30 mm (range, 7 to 147 mm). The results of the stepwise multiple regression analysis showed that a history of hysterectomy and the length of the ERP were significantly associated with the presence of enterocele. The analysis showed that the longer the prolapse, the higher the incidence of enterocele. A history of hysterectomy was also significantly associated with the presence of rectocele.Conclusion: Patients with ERP often have associated anatomical abnormalities and should be investigated thoroughly before planning surgical treatment.

Role of Breast Tomosynthesis in Diagnosis of Breast Cancer for Japanese Women

Takamoto, Yayoi,Tsunoda, Hiroko,Kikuchi, Mari,Hayashi, Naoki,Honda, Satoshi,Koyama, Tomomi,Ohde, Sachiko,Yagata, Hiroshi,Yoshida, Atsushi,Yamauchi, Hideko Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.5

Introduction: Mammography is the most basic modality in breast cancer imaging. However, the overlap of breast tissue depicted on conventional two-dimensional mammography (2DMMG) may create significant obstacles to detecting abnormalities, especially in dense or heterogeneously dense breasts. In three-dimensional digital breast tomosynthesis (3DBT), tomographic images of the breast are reconstructed from multiple projections acquired at different angles. It has reported that this technology allows the generation of 3D data, therefore overcoming the limitations of conventional 2DMMG for Western women. We assessed the detectability of lesions by conventional 2DMMG and 3DBT in diagnosis of breast cancer for Japanese women. Methods: The subjects were 195 breasts of 99 patients (median age of 48 years, range 34~82 years) that had been pathologically diagnosed with breast cancer from December 20, 2010 through March 31, 2011. Both conventional 2DMMG and 3DBT imaging were performed for all patients. Detectability of lesions was assessed based on differences in category class. Results: Of the affected breasts, 77 (75.5%) had lesions assigned to the same categories by 2DMMG and 3DBT. For 24 (23.5%) lesions, the category increased in 3DBT indicating improvement in diagnostic performance compared to 2DMMG. 3DBT improved diagnostic sensitivity for patients with mass, focal asymmetric density (FAD), and architectural distortion. However, 3DBT was not statistically superior in diagnosis of the presence or absence of calcification. Conclusions: In this study, 3DBT was superior in diagnosing lesions in form of mass, FAD, and/or architectural distortion. 3DBT is a novel technique that may provide a breakthrough in solving the difficulties of diagnosis caused by parenchyma overlap for Japanese women.

A Proposal for Service Satellite Selection over LEO Satellite Networks Using Geographical Location Information

Dharmaratna, Umith,Tsunoda, Hiroshi,Kato, Nei,Nemoto, Yoshiaki 통신위성우주산업연구회 2003 Joint Conference on Satellite Communications Vol.2003 No.-

Since LEO(Low Earth Orbit) satellite move relative to Earth, handovers are required from time to time. Some LEO satellite networks have satellites orbiting in two different direction. One from north to south and one from south to north. Communication between satellites orbiting in different directions can take place only through the polar region. Therefore when terminals are connected to satellites orbiting in different directions propagation delay in longer than when they are connected to satellites orbiting in the dame direction. Usually two satellites can be seen by a ground terminal, one satellite orbiting in each direction. Conventional service satellite selection method, select the satellite which has the highest angle of elevation to handover a terminal, which can result in two communicating terminal getting connected to satellite orbiting in different directions. In the case of handover between satellites orbiting in different directions the degradation of communication quality is higher due to drastic change in delay. In this paper we propose a satellite selection method to connect communicating terminals to satellites orbiting in the same direction, using geographical location information of the communicating terminals. We show through simulation that the proposed method reduce the delay and jitter, number of hope required for communication as well as congestion in polar region link.

Early postoperative outcomes of a novel nonexcisional technique using aluminum potassium sulfate and tannic acid sclerotherapy with mucopexy on patients with grade III hemorrhoids

Takada Shunya,Tsunoda Akira,Takahashi Tomoko,Kusanagi Hiroshi 대한대장항문학회 2022 Annals of Coloproctolgy Vol.38 No.4

Purpose: Aluminum potassium sulfate and tannic acid (ALTA; Zion, Mitsubishi Pharma Corp.) is an effective sclerosing agent for internal hemorrhoids. ALTA therapy with a rectal mucopexy (AM) is a new approach for treating hemorrhoidal prolapse. This study compared the early postoperative outcomes of AM surgery with Doppler-guided transanal hemorrhoidal dearterialization and mucopexy (DM) in patients with third-degree hemorrhoids. Methods: AM surgery was performed on 32 patients with grade III hemorrhoids and was compared with a cohort of 22 patients who underwent DM surgery in a previous randomized controlled trial. Results: The pain scores during defecation were significantly lower in the AM patients beginning 4 days after surgery. The total use of analgesics 2 weeks postoperatively was significantly lower in the AM patients than in the DM patients (3.5 tablets [range 1.6–5.5] vs. 7.6 tablets [range 3.3–11.9], P=0.04). The length of operation, blood loss, and incidence of postoperative complications were significantly lower in the AM patients than in the DM patients. During 12 months follow-up, recurrence of prolapse occurred in 1 patient who underwent AM surgery. Conclusion: AM surgery is effective, with lower complication rates and postoperative analgesic requirements, and is a less invasive treatment for patients with grade III hemorrhoids compared to DM surgery.