A Deployment of Fine-Grained Sensor Network and Empirical Analysis of Urban Temperature

Temperature in an urban area exhibits a complicated pattern due to complexity of infrastructure. Despite geographical proximity, structures of a group of buildings and streets affect changes in temperature. To investigate the pattern of fine-grained distribution of temperature, we installed a densely distributed sensor network called UScan. In this paper, we describe the system architecture of UScan as well as experience learned from installing 200 sensors in downtown Tokyo. The field experiment of UScan system operated for two months to collect long-term urban temperature data. To analyze the collected data in an efficient manner, we propose a lightweight clustering methodology to study the correlation between the pattern of temperature and various environmental factors including the amount of sunshine, the width of streets, and the existence of trees. The analysis reveals meaningful results and asserts the necessity of fine-grained deployment of sensors in an urban area

"Lost Decade" - Economic Development of Japan in the 90s of the 20th century

Tato bakalářská práce analyzuje ekonomickou situaci v Japonsku v 90. letech 20. století tzv. Ztracenou dekádu. Práce se částečně dotýká bubliny nemovitostí na konci 80. let 20. století a jejím hlavním zaměřením je role jednotlivých opatřeních přijatých vládou a Japonskou centrální bankou v následujících 90. letech. Analyzuji jednotlivá rozhodnutí pomocí statistik, vědeckých článků a názorů různých ekonomů. Dále se tato práce zabývá také kulturním pozadím, rolí spotřebitele a významnými zahraničními událostmi, které toto období ovlivnily. Posouzením všech těchto informací a různých ekonomických názorů docházím k závěru, že i když mnoho fiskálních a monetárních rozhodnutí bylo myšleno správně a v dané situaci se ani pravděpodobně nešlo rozhodnout příliš rozdílně, nepřihlédnutím k specifickým kulturním podmínkám dané ekonomiky došlo k zhoršení situace nebo alespoň k prodloužení trvajícího neuspokojivého stavu ekonomiky.This bachelors thesis deals with Lost Decade, the 1990s in Japan. The work is slightly touching a subject of real estate bubble at the end of the 1980s and the main focus is on the individual measures taken by the government and Bank of Japan in the following 90th. I'm analyzing individual measures with the help of statistics, academic articles and opinions from various economists. The thesis also deals with cultural side, the role of consumers and significant foreign events, which affected this period. By evaluating all these informations and economic thoughts, I come to conclusion, that even if many monetary and fiscal decisions were in their core right, by not considering special local cultural differences of Japan economy, it led to the worse economic situation or at least to prolonging the not so good state of economy

Simulation and measurement of ferromagnetic impurities in non-magnetic aeroengine turbine disks using fluxgate magnetometers

In this paper, ferromagnetic impurities in paramagnetic aeroengine turbine disks are investigated. Because such inclusions represent a significant threat in aviation, a detailed analysis is required for impured turbine disks. For this purpose, sensitive fluxgate magnetometers are used. After a premagnetisation, this sensor is able to detect small ferromagnetic particles by recording the variation of the magnetic flux density while the disk rotates below the sensor head. This trajectory creates a unique signature. However, the measured signatures are often distorted. A main reason for these distortions is that the particles are not oriented in axial direction (in the direction of the disks axis). Up to now, it was not possible to interpret the measured signatures. Thus, a simulation tool has been developed that provides a catalogue of different magnetic flux density distributions of typical orientations, positions and various distances to the fluxgate magnetometer position. For these simulations, the particles are assumed to be dipoles. As part of impurities are not caused by concentrated particles but by elongated ones, so-called or dipole lines, the model has been expanded for these cases by using numerical integration techniques. Measurements verify the assumption to approximate impurities by dipoles

Fusion of radar and optical images for person screening in security sensitive environments

Recent terror attacks showed the vulnerability of our public life. That is why, a lot of security systems have been developed; especially for person screening on airports. However, sometimes images with anatomic details are produced violating the human privacy rights. To avoid it, mostly stylised avatars are shown on which the locations of the detected prohibited items on the body are marked. This, however, gives only a coarse orientation. In this paper, a better way is proposed by fusing the images of a radar sensor and an optical sensor. The radar image is generated by a rotating millimetre wave FMCW radar operating between 96 GHz and 99 GHz. It consists of a one transmitter and five receivers in order to scan the person from different aspect angles. The RF front end consists of a monolithic microwave integrated circuit with a chip size of 2x3 mm. The circuit features coplanar technology and cascode HEMTs for compact size and low cost. The optical image is generated by a time of flight (ToF) camera system which is able to measure the distance between the camera and a reflecting point by measuring the elapsed time. Hence, the ToF principle is quite similar to a radar (active ranging system), that needs an illumination source. To measure the distances, the light has to be modulated adequately. Then, it is possible to evaluate it as the modulation of the back-scattered signal differs from that of the emitted one. Mostly, the near infrared area is used for this purpose, because it is invisible and simultaneously not harmful for the human eye. Both, optical and radar image are superimposed showing the exact location of concealed objects worn under the cloths. For this purpose, perspective distortions are removed by a complex mathematic model considering the dimensions and the physical inner structure of the CMOS ToF chip array

Sensor fusion based security concept on airports with a rotating millimetre wave person scanner

This paper gives an overview about a new security concept on airports. Because single systems have not often the desired reliability, the concept is based on the fusion of different sensors. Moreover, first measurements of a 94 GHz person scanner with circular synthetic aperture are presented showing the capability to detect metallic as well as nonmetallic objects without violating the personal privacy