Tsukuba City Research Articles

平成24年5月6日に茨城県常総市からつくば市にかけて発生した竜巻による森林被害

平成24年5月6日に茨城県常総市からつくば市にかけて発生した竜巻による森林被害

Multimodal direct fitting of SPAC coefficients using amplitude response

We usually analyse microtremors without any considerations of higher modes of surface waves. However, recent studies have demonstrated that the use of higher modes would improve estimated velocity models. In this study, we apply multi-mode analysis with amplitude response to the direct fitting method in SPAC method. The proposed method has the advantage that we don?t need to identify observed modes, which can avoid mode misidentification. The proposed method was applied to synthesized microtremors. Estimated SPAC coefficients were good agreed with theoretical ones proposed in this study, even if in the frequency where two modes have about the same power fractions. The S-wave velocity was then successfully inverted by the direct fitting of SPAC coefficients. The proposed method also works well in the analysis of field data acquired in Tsukuba City, Japan. In the inversion performed in this study, we do not use prior information about velocity structure. It is concluded that the multi-mode analysis proposed here is very robust in the multimodal analysis in SPAC method.

Atlantic hurricanes and associated insurance loss potentials in future climate scenarios: limitations of high-resolution AGCM simulations

Potential future changes in tropical cyclone (TC) characteristics are among the more serious regional threats of global climate change. Therefore, a better understanding of how anthropogenic climate change may affect TCs and how these changes translate in socio-economic impacts is required. Here, we apply a TC detection and tracking method that was developed for ERA-40 data to time-slice experiments of two atmospheric general circulation models, namely the fifth version of the European Centre model of Hamburg model (MPI, Hamburg, Germany, T213) and the Japan Meteorological Agency/ Meteorological research Institute model (MRI, Tsukuba city, Japan, TL959). For each model, two climate simulations are available: a control simulation for present-day conditions to evaluate the model against observations, and a scenario simulation to assess future changes. The evaluation of the control simulations shows that the number of intense storms is underestimated due to the model resolution. To overcome this deficiency, simulated cyclone intensities are scaled to the best track data leading to a better representation of the TC intensities. Both models project an increased number of major hurricanes and modified trajectories in their scenario simulations. These changes have an effect on the projected loss potentials. However, these state-of-the-art models still yield contradicting results, and therefore they are not yet suitable to provide robust estimates of losses due to uncertainties in simulated hurricane intensity, location and frequency.

Development of a Mobile Robot to Run in Tsukuba Challenge 2010

This paper describes an implementation of a mobile robot system in a 1 km autonomous mobile robot navigation challenge called ‘Tsukuba Challenge 2010’ which was held in the city of Tsukuba, Ibaraki, Japan. The mobile robot used only three types of sensors which were a magnetic sensor, two wheel encoders, and a laser range finder. For a stable navigation, we have proposed a method that is able to localize and perform trajectory tracking based on patterns of the magnetic field's intensity that occurs in the environment. It was divided into two distinct parts of map building and navigating. In the map building, the mobile robot was operated by a joystick along the course of the challenge to record the environmental magnetic field to build a map. The mobile robot then navigated by using a trajectory tracking method based on the map. During the seven trials which were given before the qualifying and final runs, the mobile robot completed the full course three times with once in small rain.

Tsukuba Biomass Town Initiative

Tsukuba city has been promoting projects to reduce 50% CO2 emission per capita by 2030. One action plan is creation of a low-carbon rural area including acceleration of biomass use. Biomass Task Force was established aiming at planning of Biomass Town, and implementation of social experiment on biomass use. Interim achievements such as investigation result of present biomass use situation, ideas of biomass use including algae, and preparation of road map to promote biomass use, are arranged. It is essential to have reliable cooperation among related sectors, good institution, funds and suitable technologies at several points in time.

保護者による許可から捉えた子どもの移動自由性と屋外遊びとの関連の地域差

Children’s “independent mobility”, measured by parental license on children’s activities, means the ability of children to walk their neighborhood without adult accompaniment. Recently, concerns have been raised that decreasing children’s independent mobility negatively correlate with outdoor play of children in many developed countries. Although the relationship between children’s independent mobility and children’s outdoor play assumes to depend on the characteristics of the area children lived, it is not clear. This study aims to identify the area difference of the relationship between children’s independent mobility and their outdoor play. From a questionnaire survey of 2861 children and 2196 parents in five elementary schools located in Tsukuba City, we found the following results. a) Independent mobility of children living in rural areas is lower than those who live in urban areas. b) Children’s independent mobility tends to correlate positive with the number of types, playmates and, places of children’s outdoor play. c) The positive correlation between children’s independent mobility and their outdoor plays in rural areas is stronger than urban areas. d) The reasons of low level of independent mobility in rural areas are longer distance to children’s playgrounds from their homes, parental perceived danger against traffic or crimes, and parental low level of perceived support to their children from their neighborhoods. In conclusion, we discuss the area difference of the relationship between children’s independent mobility and their outdoor play.

Community Activities to Protect Children from Crime, People's General Trust, and Attitude toward the Activities in Japan

We distributed questionnaire booklets to households in Tsukuba city, Japan. The questionnaire included questions regarding attitudes toward local crime prevention activities, perception about public safety and crime related anxiety, and sociodemographic variables. The result showed that elder people have much stronger attitude toward community crime prevention compared to younger people. The result also showed that people who have more emergent sense of crisis about their community tend to have an attitude that community crime prevention is their own issue, and people who have inconsistent fear of crime tend to have an aloof attitude toward community crime prevention activities.

Tornedo disaster of Tsukuba City on May, 2012

Tornedo disaster of Tsukuba City on May, 2012

つくば市周辺地域における三次元水文地質モデルの構築と帯水層の透水性の推定への適用

Three-dimensional earth sciences information is being made available in digital formats because such information is useful and understandable to various users. In this study, we develop a three-dimensional hydrogeological model of Tsukuba City and the surrounding region, and develop a method for estimating the hydraulic conductivity of aquifers in combination with the three-dimensional hydrogeological model and other related hydrogeological information with the primary objective of proposing a method for evaluating groundwater resources. The three-dimensional hydrogeological model was developed using a geological map and drilling data with data interpolated using a geostatistical method. The model developed reproduced the data used well, and it was found to be accurate for practical use. Moreover, this model could be used for various types of visualization, from which information could be extracted and applied immediately to numerical simulations; this provided information that was useful and understandable for evaluating groundwater resources. The proposed method for estimating the hydraulic conductivity of aquifers was developed from hydraulic conductivities obtained from various drilling surveys, which were grouped together taking geology and stratigraphy into consideration based on a three-dimensional hydrogeological model, and using a statistical analysis. This method can be used to rapidly evaluate trends in hydraulic conductivity by integrating data distributed over a broad area. In addition, if a columnar section of an evaluated point is obtained, this method can be used to determine the actual hydraulic conductivity of aquifers. Therefore, these methods were found to be effective for evaluating groundwater resources.

Construction of an analytical framework for polygon-based land use transition analyses

Polygon representation is important for characterizing land uses and the relationships among them. This study aims to establish an analytical framework for polygon-based land use transitions to understand the processes of change regarding types of land uses and their shapes. The polygon event and polygon state help to reveal continuity both spatially and temporally. A polygon event represents a combination of changes in both the type of land use and its shape through a transition process. A polygon state reflects homogeneity during the transition process. Two indices, the stability index and the compactness, were used to enhance the understanding of the transition process. The stability index evaluates the succession of an attribute, while compactness recognizes the geometrical characteristics of a polygon. A case study on Tsukuba City, Japan, was evaluated to demonstrate the feasibility of the approach that is presented here. The proposed analytical framework supports the clarification of land use transition patterns and is effective in explaining the spatiotemporal land use transition process.

Analytical framework for polygon-based land use change

Polygon representation is important for characterizing land use and the relationships among the land use polygon. This study aims to establish an analytical framework for polygon-based land use change to understand the land use change process considering types of land use and the shape. Polygon event and polygon state help to grasp the continuity spatially and temporally. Polygon event represents the combination of both changes in type of land use and the shape through the change process. Polygon state reflects homogeneity during the change process. Compactness, which recognizes geometrical characteristics of a polygon, was used to enhance understanding of the change process. A case study in Tsukuba City, Japan was tested to demonstrate the feasibility of the presented approach. The proposed framework supports the clarification of land use change pattern and is effective in explaining the spatio-temporal land use change process.

Time Variations in Dose Rate and γ Spectrum Measured at Tsukuba City, Ibaraki, due to the Accident of Fukushima Daiichi Nuclear Power Station

The time variations in the dose rate and γ spectrum of radio nuclides originating from the accident of Fukushima Daiichi Nuclear Power Station were measured at Tsukuba City, Ibaraki, during the period from 15th March to 9th April 2011. The radiation dose peaked three times during the period from 15th to 16th March (1.27 μSv/h at maximum). The contribution of Xe-133 to the dose rate was observed from the γ spectrum obtained from the 5 h measurement during the peaks on 15th and 16th March, indicating that radioactive plume passed through Tsukuba City at that time. After the peaks, a dose rate increase with rainfall was observed on 21th March, dominating the integral dose rate measured at Tsukuba City. The dose after the rainfall comes from I-131, Cs-134, and Cs-137 that can be observed as peaks in the spectra.

1P1-K14 占有格子地図とA*アルゴリズムを用いた実時間障害物回避経路生成(車輪型/クローラ型移動ロボット)

Safe, robust and reliable technologies are needed for service robots with autonomous traveling capabilities to put them into wide use. Especially, robust localization and safe obstacle avoidance in human-shared outdoor environments are mainly discussed in recent research works. 'Tsukuba Challenge' has been held as a robot competition for autonomous traveling ability in real-world by New Technology Foundation and Tsukuba City since 2007. The task of Tsukuba Challenge 2010 was completing the autonomous traveling in the course which includes pedestrian, park, sidewalk, plaza, bridge, stc. The total distance of the course was approximately 1.1 km. Moreover, Tsukuba Challenge 2010 required avoiding capability against other robots for adaptation to the dynamically changeable real-world. We joined Tsukuba Challenge 2010 as a team "Schuderia Frola AIST" and developed the intelligent wheelchair robot 'Marcus'. The newly-developed real-time obstacle avoidance ability was installed on the robot. This method creates and updates occupancy grid map which records obstacle information from laser range finder (LRF) and generates the avoiding route using A* search algorithm. The effectiveness of the method was demonstrated experimentally in the human-shared outdoor environments in Tsukuba Challenge 2010.

A system model for estimating regional cross-pollination rates between GM and non-GM rice considering actual meteorological conditions and field distributions

To sustain a stable food supply without losses from various hazards, such as insects, diseases, or abnormal climate conditions induced by global change, application of genetically modified (GM) organisms is one potential tool for agriculture. However, GM crops do not exist in traditional agricultural environments; thus, the risks resulting from the application of GM crops to agriculture must be made clear. Crops, such as rice belonging to the Gramineae family, can be cross-pollinated by wind. This enables non-GM crops to be pollinated by GM crops. Prior to the cultivation of GM crops, the degree of cross-pollination must be estimated. This should take into consideration meteorological conditions, because of their importance in pollen flow. We constructed a system model to calculate the cross-pollination distribution by using data on the geographical distribution of GM donor and non-GM recipient crop fields, meteorological elements, and flowering data. The system consists of a main program to calculate cross-pollination rates, a program to include the isolation distance, and a sub-program to average the maps of the cross-pollination rates in recipient fields. The system can predict the regional cross-pollination rate by incorporating the isolation distance and differences in the flowering period. The system was applied to three areas around Tsukuba City, Ibaraki Prefecture, with different distributions of paddy fields and hypothetical donor (ratio 30%) and recipient (ratio 70%) fields. The general trend was that the cross-pollination rates were lower in areas of clustered donor fields. The calculated cross-pollination rate can mostly be explained by the length of the border between the donor and recipient fields. This is because rice pollen is dispersed only within short distances from donor fields. In order to clarify the influence of meteorological conditions on the variation in the cross-pollination rate, 10 years of simulations were performed. The cross-pollination rate varied by about a factor of three (0.03-0.09% for one of the simulated fields) during the simulated 10 years.

Evaluating Administrative Efficiency Change in the Post-Merger Period

This article analyzes the change in municipal administrative efficiency in the post-merger period using the data of 92 municipalities in Ibaraki prefecture for the period 1979–2004. For this purpose, the authors employ a nonparametric programming method to compute a data envelopment analysis (DEA)/Malmquist indices (MI). These indices are decomposed into two component measures, namely, catch-up (CU) and frontier shift (FS) indices. The authors found that the administrative efficiency in Ibaraki prefecture in the post-merger period was monotonically regressed; however, the efficiency scores of merging municipalities were found to be higher than those of nonmerging ones. Scale change did not necessarily contribute to an efficiency change in the post-merger period. In the short run, scale affected Tsukuba city, which was formed by consolidating smaller municipalities.

Effects of Tsukuba Express Project on the Residents' Travel Behavior

The Tsukuba Express line commenced operations in August 2005, connecting Tsukuba city and Tokyo metropolitan, Japan. Based on the Tsukuba Express Railway Project, the transportation system includes road network and local bus network which had greatly restructured Tsukuba City and its surrounding area. The objective of this paper is to understand the impact of Tsukuba Express Railway Project on the actual travel pattern and behavior of the residents of the surrounding areas of Tsukuba Express. The study conducted panel data survey before and after Tsukuba Express' operation. Results indicated that residents' patterns and modal choices have changed significantly.

Petrography of cuttings from spa borings and their tectonic setting upon the Kanto Plain at Shimohara, Tsukuba city and at Hanai, Noda city

This report describes the subsurface geology, based on the petrography of rock cuttings taken from bore holes at spa sites, at Shimohara, Tsukuba City, Ibaraki Prefecture, and at Hanai, Noda City, Chiba Prefecture, both upon the Kanto Plain. The cutting samples from Tsukuba (four samples from 1241–1210 m depth) are hornfels, biotite-muscovite schist, and sillimanite-andalusite gneisses that resemble the Tsukuba metamorphic rocks. A single cutting sample from Noda (1295–1300 m depth) is mylonitized biotite granite that is similar in lithology to the Late Cretaceous Name Granite in the Shimonita area, Gunma Prefecture. These results provide new information on the eastern extension of the Ryoke Metamorphic Belt and the southern extension of the Tsukuba Metamorphic Belt. The occurrence of mylonite from Noda also provides important information in terms of constraining the eastern extension of the Median Tectonic Line.

THE EFFECTS OF A SERIES OF WINDBREAKS ON THE MICLOCLIMATE IN A SETTLEMENT IN WINTER

The objective of this study is to clarify the effect of a series of windbreaks on the microclimate in a settlement. Horage settlement is located in Tsukuba City where the seasonal cold wind called“Tsukuba-Oroshi”blows in winter, and that settlement is surrounded with windbreaks. Field observations of air temperature, humidity, wind direction and velocity were conducted in winter of 2006 and 2007. The protecting effect of windbreaks against the seasonal prevailing wind was observed clearly in the daytime when the strong wind blew in the observation area. Wind velocity in the built-up area was decreased with about 45% of that in the outside of the settlement. The heat island appeared clearly in the early morning and at night when the wind was weak or calm. Daily ranges of air temperature were small in the northeast area covered with dense windbreak woods.

Emergency Medical Support System for Extravehicular Activity Training Held at Weightless Environment Test Building (WETS) of the Japan Aerospace Exploration Agency (JAXA)

The Japan Aerospace Exploration Agency (JAXA) provides extravehicular activity (EVA) training to astronauts in a weightless environment test building (WETS) located in Tsukuba City. For EVA trainin...

Reginal Changes along “Tsukuba Express” in Tsukuba City, Ibaraki prefecture

Reginal Changes along “Tsukuba Express” in Tsukuba City, Ibaraki prefecture