LED-to-camera communication for smartphones promises to enable low-cost, small-size, and intuitive data access to Internet-of-things (IoT) devices. However, for fast and reliable communication under the rolling shutter effect, the packet losses caused by inter-frame gaps and frame drops must be dealt with. In this paper, we introduce LED-to-camera communication between a commercial smartphone and an IoT device with LED flashlight, where the user can intuitively acquire the desired data transmitted from the IoT device to the smartphone. Specifically, we present IoTorch, a fast and reliable LED-to-camera communication that efficiently prevents the packet losses. IoTorch consists of two core mechanisms: 1) a minimum-repetition one-way reliable transmission focusing on the periodicity of inter-frame gaps and 2) an acknowledgement mechanism to overcome frame drops by using a smartphone's built-in flash focusing on its delay characteristics. Additionally, we propose an optimization method to increase the throughput up to 2.92 kbps (i.e., 2.43 times faster than that of the state-of-the-art method that overcomes the inter-frame gaps). Furthermore, we realize a remote wake-up function by using the smartphone's flash as the data transmission trigger. To demonstrate the benefit of IoTorch, we present a sensor data viewer using Arduino and a smartphone console system on TelosB.

Band selection study for SMILES-2 proposal (JAXA/ISAS 500 kg science satellite program) is updated from 4 bands configuration to 3 bands (625-650 GHz, 750-771 and 1.8- 2.0THz). This change is required to reduce sizes of primary antenna (from 100 cm to2, CO, CH3Cl, and BrO, is improved in the new 3 bands configuration.

SMILES2 is a mission prepared for the next call-for-proposals for JAXA/ISAS M-class scientific satellite mission. It aims at scanning the atmospheric limb from 20 to 160 km above the surface at frequencies near 700 GHz and 2 THz. It could provide the temperature and composition as well as, for the first time, the horizontal wind vector above 30 km, the atomic oxygen in its ground state above 90 km, and the atmospheric density and the geomagnetic field vector near the mesopause. The mission is proposed for the 2ndtime and the instrument design has been improved for accounting for the recommendations of the review committee. In this publication, we discuss the measurement performances assessed from simulations including latest results showing the mission potential for measuring the geomagnetic field between 70-110 km.

The Superconducting Submillimeter-Wave Limb-Emission Sounder-2 (SMILES-2) is a satellite mission for observation of the stratosphere, mesosphere, and lower thermosphere with superconducting submillimeter-wave receivers, being proposed to the announcement of opportunity for M-class missions run by the Japan Aerospace Exploration Agency (JAXA). The SMILES-2 notable features are extremely high sensitivity and observation capability of atmospheric diurnal cycles. Those are requested from a scientific requirement for the investigation of the 4-D space-time structure of diurnal variations in the whole atmosphere. Such features require SMILES-2 to have 4–K cooled superconducting devices for high sensitivity and to be aboard a satellite platform on a non-sunsynchronous orbit. The mechanical 4–K cooling system is a power consuming instrument. Satellite on a non- sunsynchronous orbit gets a large sun-shade ratio in most of season, and has limitations of power supply to the mission instrument. The issue of the SMILES-2 mission design is mainly to fit the 4–K cooling system to the limited power resource of M-class satellite. This paper discusses our development status on designing the SMILES-2 mission payload. SMILES-2 will be proposed to JAXA in the beginning of the next year.

The Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) on the International Space Station demonstrated a 4 K mechanical cooler for high-sensitivity submillimeter limb-emission sounding of atmospheric observations. Based on the SMILES heritage, we propose a satellite mission "SMILES-2" to observe temperature and wind fields, and distributions of atmospheric trace gases from the middle atmosphere to the upper atmosphere. We will be able to grasp the 4-D dynamical structure of diurnal variations which are one of the most essential characteristics in the earth's atmosphere. In the upper atmosphere, a transition layer between the atmosphere and the outer space, we will be able to clarify a role of magnetospheric energy inputs from the temperature and wind observations. These outcomes including the atmospheric trace gas data will greatly contribute to improve the reliability of chemistry climate models for future projection and the accuracy of prediction models for space weather.

This paper proposes a system that estimates crowdedness, such as the numbers of people and wireless communication devices, from the received signal strength indication (RSSI), which is measured using sensor nodes already-deployed for a different purpose. For example, the system estimates crowdedness using sensor nodes of structural health monitoring. Our system consists of two parts: an RSSI synchronous measurement and a crowdedness estimation algorithm. The RSSI synchronous measurement enables us to measure and collect two kinds of RSSI by synchronized RSSI sampling: the inter-node RSSI and surrounding RSSI. The crowdedness estimation algorithm estimates the number of people from the collected inter-node RSSI and the number of wireless communication devices from the collected surrounding RSSI in a location. We evaluated the proposed system in the laboratory at Osaka University. The evaluation results demonstrate that the system estimates the presence or absence of people in the laboratory with approximately 92% accuracy and the number of people with approximately 79% accuracy, with errors of up to two people.

LoRa networks achieve a remarkably wide coverage as compared to that of the conventional wireless systems by employing the chirp spread spectrum (CSS). However, single-hop LoRa networks have limited penetration in indoor environments and cannot efficiently utilize the multiple-access dimensions arising from different spreading factors (SF) because the star topology is typically used for LoRa. On the other hand, a multi-hop LoRa network has the potential to realize extensive network coverage by utilizing packet relaying and improving the network capacity by utilizing different SFs. We evaluated the LoRa receiver performance under co-technology interference via simulation and experiments to realize these potentials. The results show that LoRa can survive interference from time-synchronized packets transmitted by multiple transmitters with an identical SF. Furthermore, we examined the orthogonality between different SFs by evaluating the required signal-to-interference ratio (SIR). Finally, we demonstrated the possibility of employing different SFs to construct the pipeline in a multi-hop relay network to increase network efficiency.

The Superconducting Submillimeter- Wave Limb-Emission Sounder 2 (SMILES-2) is a satellite mission to observe the stratosphere, mesosphere, and lower thermosphere with superconducting submillimeter receivers. SMILES-2 aims at studying the dynamical, chemical, and electromagnetic coupling of the middle and upper atmosphere with an unprecedented high-precision observations of multiple atmospheric parameters from a platform on a non-sunsynchronous orbit. SMILES-2 consists of superconducting receivers at frequencies between 619 GHz and 2.06 THz. The GHz receivers observe mainly the temperature, wind, and chemical compositions in the stratosphere and mesosphere. The frequency band of 640 GHz receiver includes the band investigated by JEM/SMILES mission, which was operated during the period from 2009 to 2010. The THz receiver, a new channel of SMILES-2, is devoted to measurement of atomic oxygen for observation of the lower thermospheric temperature and wind. The SIS mixer of GHz receiver and HEB mixer of THz receiver are cooled down to around 4 K by a mechanical cryocooler, which is designed to have 3 year lifetime and 5 year goal. The SMILES-2 payload is estimated to be less than 200 kg and consume power of 300 to 400 W. SMILES-2 is proposed for a mission installed on 500 kg size satellite of the Japan Aerospace Exploration Agency (JAXA).

This paper proposes to adopt concurrent trans- mission in a distributed antenna system to achieve the real- time capability and reliability for wireless automation systems. Our scheme is the simplest way to realize spatial diversity by deploying a large number, e.g. several tens, of transmit antennas and allow all of them to participate in simultaneous packet transmission without any cooperation. We examine the performance, including packet error rate and high- reliability area percentage, in simulation and over-the-air experiments under the IEEE 802.15.4 standard, where the experiments are conducted with up to 32 concurrent transmitters using Tmote Sky sensor nodes. We found that the presence of a timing offset limits the performance. By lowering the timing offset to be below half of a chip period, the reliable performance can be achieved without sacrificing the real-time capability.

Real-time and robust communication is essential for wireless control systems (WCS). Preambles are considered as significant communication overheads in WCS where payloads are typically small. To shorten the overhead in OFDM systems, previous works have considered fixed subcarrier sampling to obtain subcarrier-fixed short preambles (SFSP) and adopted frequency-direction interpolation (FDI) for channel estimation. Despite of advantage in fast fading channel, it results in poor performance in frequency-selective fading channel. In this work, we propose a subcarrier-selectable short preamble (SSSP) which provides full sampling coverage of all subcarriers with several preamble transmissions. By exploiting the periodicity of transmissions in WCS, the SSSP scheme obtains the channel estimation of non-selected subcarriers by not only FDI but also the time-direction extrapolation (TDE), which is robust in frequency-selective fading. In addition, in order to make the channel estimation robust in both fast fading and frequency-selective fading we adopt an adaptive algorithm altering between FDI or TDE mode. The feasibility of the proposed method is validated by evaluating symbol error rate (SER) in fast frequency-selective fading. Simulation results verify that unlike the SFSP the adaptive SSSP scheme shows no error floor in SER curve when the channel is frequency-selective fading, and performs similar to the SFSP scheme when the channel is fast fading.

Many works attributed the successful reception of concurrent transmission (CT) to the constructive interference. However, due to the inevitable carrier frequency offset (CFO) and the resulted beating effect, the claim of constructive interference is actually not valid. To clarify the reason behind the successful receptions under CT, we conduct extensive evaluations and identify the following findings. 1) We show that the IEEE 802.15.4 receivers survive the beating effect mainly because of the direct sequence spread spectrum (DSSS), while systems without the protection of DSSS are not applicable to CT. 2) We identify a counterintuitive phenomenon that the IEEE 802.15.4 receiver could survive only the beating results from large CFO, while performing poorly when CFO is small. 3) We demonstrate that, even if the receivers survive, CT links lead to little performance improvements compared to conventional signal transmission links from the SNR point of view.

Many researches have shown that concurrent transmission (CT) helps to improve the energy efficiency and latency of 2.4GHz IEEE-802.15.4-based multi-hop networks. However, it has been shown that the success of CT in IEEE 802.15.4 is mainly due to the DSSS. In view of the great potential of long range sub-GHz technologies for future smart meter applications, we assess the feasibility of applying CT to non-DSSS sub-GHz receivers. In this work, we evaluate the FSK-based receiver performance in the critical case - the scenario that concurrent transmitted signals are received with the same power such so the mutual interference become worst. Our evaluations are based on the 2-FSK mode of TI CC1120 chips. The results show that the basic 2-FSK mode is vulnerable to CT. On the other hand, if the FEC and the interleaver are adopted, the receiver can survive in the heavy interfering region as long as the timing offset is smaller than 1 μs and the CFO is larger than 5 KHz.

This paper presents an RSSI-based packet combining (PC) scheme to improve the packet reception reliability affected by a beat interference in wireless sensor networks (WSN) using concurrent transmission (CT). To overcome the beat problem, our PC scheme exploits multiple receptions to perform simple post-detection selection combining based on RSSI values. An implementation verifies its feasibility in resource-limited sensor nodes with time-sensitive CT. Evaluations using computer simulations and hardware experiments show significant reliability improvement.

Laser retina imaging technology enables creation of a clear picture in any retina area. It is focus-free, i.e. irrelevant of refractive disorder. So in many cases of low vision, one can see the picture by one's own eyesight. In this article we describe possible applications of this emerging technology, including 1. Development of eyesight-aid for low vision, an HMD (headmounted display) on which this technology is implemented, 2. Creating a vision sensitive area map of retina, a novel notion, precisely. Especially this may innovate perimetry technologies in ophthalmology important in finding disorders in vision. We list up requirements for the eyesight-aid, including a compensation of partial visual field loss. Finally we indicate that part of our requirements is feasible by presenting our preliminary experiments. Indeed, we show that it is possible to detect a pictogram (“Exit”) and pedestrian boundaries on the road-side both in the view by existing pattern recognition programs (SURF method).

We report an initial investigation of the new location method of a very high frequency (VHF) radiation source, using signals recorded at the International Space Station. A VHF interferometer (VITF) has two VHF sensors. Locating lightning with VHF bands is useful to locate the position of the charge distribution in the thunderstorm. The location method of a radio source proposed used two direction-of-arrival estimation techniques. One is the interferometric technique, and another is based on the ionospheric propagation delay measurement of received signals. The combination of the two techniques provides two angular positions of the radiation source. When an altitude of a radiation source is assumed, we can determine two possible positions. One of the two positions was associated with the radiation source, while the other was not. In this paper, we compared the position of lightning and sprite imager (LSI) data, which are simultaneously captured during a lightning emission, with the locating position near the emission. The data set of the VITF within 100 ms of the optical lightning emission captured with the LSI was used. The temporally simultaneous event seems to be associated with the same lightning event. The estimated radiation positions were spatially in close agreement with the optical lightning positions captured with LSI, under nighttime ionosphere conditions. From statistical analysis, the spatial difference of the standard deviation changed from 15.3 to 30.8 km depending on the installation direction of the VHF sensors. The usefulness and limitations of the method are also discussed.

Temperature, wind speed, H2O, and O3retrieval performance in the upper stratosphere and mesosphere was estimated using 485-489 GHz sub-mm limb sounder with 500 kHz resolution (2.5 kHz resolution for wind speed). Two instrument, one is 4K-cooled successor of SMILES, and the other is a compact room temperature instrument, are considered. Temperature can be retrieved within 2K precision at 15-100 km (4K cooled) and 18-85 km (room temp). Wind speed can be retrieved within 2 m/s at 40-100 km (4K cooled) and 50-90 km (room temp). H2O can be retrieved within 5% at 20-80 km (4K cooled) and 20-70 km (room temperature).

We present a communication protocol called Choco, which efficiently supports various traffic demands with end-to-end reliability in multi-hop Wireless Sensor Networks (WSNs). To achieve this, Choco uses fine-grained scheduling based on the insight that acknowledgements (ACKs) between ends can be delivered with little overhead using concurrent transmission. Specifically, the slot assignment is dynamically scheduled up to several times a second according to traffic loads and packet losses. We show that Choco achieves higher efficiency and reliability than ORPL+BF, which is a state-of-the-art collection protocol, for periodic traffic environments. Also, we show that in a networked imaging application, which generates burst traffic, Choco can successfully collect 5 VGA images with high efficiency from 5 nodes in approximately 168~s in an average 4.0~hop network.

Theoretical sensitivity study of sub-mm limb sounder SMILES-2 (4K cooled, Tsys=250 K) proposal was conducted. Temperature and line of sight wind sensitivity,2line. BrO lines at 525.2 GHz and HOCl lines at 613.6 GHz were confirmed to have comparable theoretical sensitivities to those of SMILES and less spectral interferences by other species. 5 bands configuration (487±2, 527±2, 614±2, 626±2, 649±2 GHz) should have SMILES-like sensitivity and Aura/MLS-like chemical species coverage.

Geofencing technology enables various location-based applications by detecting entrance to a predefined region and utilizes the event as a trigger to automatic communication or control of smart devices. In this paper, we implement the proposed geofencing system on Android based smartphone and evalua

TDMA is more suitable for high throughput data collection than CSMA. Yet, in wireless sensor network plain TDMA-based protocols require complex scheduling. In case of node failures, plain TDMA is hard to recover connection and achieve robust data collection due to the complex scheduling burden. Toward robust data collection, it is important to develop a collection protocol capable of topology adaptability. We have been developing a data gathering protocol named TKN-TWN. TKN-TWN exploits the advantages of TDMA and eases the scheduling burden by using two tokens to arbitrate transmission, providing high throughput via burst data transmission. Moreover, due to the simplified scheduling based on tokens, TKN-TWN is practical to provide adaptability for infrequent topology changes. We enhance the implementation of TKN-TWN over the previous work and carry out experiment on a deployed network in the office room to evaluate the throughput and topology adaptability as well. Experimental results in the network consisting of 32 TinyOS enabled sensor nodes show that TKN-TWN is robust to network changes caused by occasional node failures. Evaluation also shows that TKN-TWN is able to even provide throughput over 10 KByte/s.

The application of a hyperspectral camera to the analysis of aerosol optical property is described. As compared with conventional instruments such as a skyradiometer, imaging measurement is advantageous because of its capability of obtaining spatial distribution of scattered solar radiation with exact identification of the solar disk position in an image. In particular, it has been demonstrated that the aureole information is useful for constraining aerosol properties.

To reduce the complexity of scheduling while exploiting the advantages of TDMA-based data collection, we propose TKN-TWN, a token-scheduled multi-channel data collection protocol. The TKN-TWN uses two tokens to arbitrate data-packet transmissions and associates the ownership of tokens with transmission slot assignment. For the reduction of scheduling burden, the TKN-TWN provides topology adaptability while maintaining high throughput in burst data transfer. In this paper, we present the system design of TKN-TWN with enhancement toward topology adaptability based on a previous work. We evaluate TKN-TWN on a local test bed using 31 TelosB sensor nodes. Evaluation results show that the TKN-TWN achieves throughput of 6.4 KByte/s with more than 99% delivery ratio even with occasional node failures.

The objective of this research is to realize a method that detects a user's entrance to predefined geographic area so that appropriate services are provided without explicit user action. Though such geofencing technology is gathering attention due to its wide range of applications, it is a challenge to overcome trade-off between power consumption and detection accuracy. Conventional variable interval positioning methods fall short on battery saving due to difficulties such as sparse and erroneous position measurement data, and the unpredictable speed and trajectory of the terminal. In this paper, we propose a method for position detection whose activation frequency is determined by speed toward the target spot. The method is robust against positioning error and fluctuation of the terminal's movement by leveraging the access angle to the target spot. Simulation results show that the proposed access speed correction method reduces power consumption from 42% to 52% against conventional method, while holding the false negative ratio to detect the target spot to less than 5%.

This paper presents a system design and experimental evaluations for ambient sound-based proximity detection with smartphones. Ambient sound is useful as spatiotemporal identifier. This is because ambient sound contains abundant information which depends on time and space. To detect proximity at high accuracy, we calculate cross correlation in frequency domain for the similarity measure of ambient sound. The results of experiments show that our system discriminates 5 rooms with the accuracy of true positive 94.9% and false positive 0.1%.

This paper presents how carrier frequency differences among transmitters affect concurrent transmission in wireless sensor networks. The carrier frequency differences cause two problems: reverse phase rotation and signal level fluctuations. The effects of these problems depend on modulation schemes. The demonstration shows these problems with moving images of superposed baseband signal and constellation transmitted from 1-6 nodes concurrently.

We present a high throughput data gathering protocol for wireless sensor network. Different from existing works we elaborate a token-scheduled multi-channel TDMA protocol named TKN-TWN that provides better scalability and topology adaptability. TDMA is more suitable for high throughput data collection than CSMA. However, TDMA-based protocols require complex scheduling of the transmission time slot. The scheduling burden is a primary stumbling block of topology adaptability. To ease the scheduling burden while exploiting the advantages of TDMA, we propose to use two tokens arbitrate transmission and associate the ownership of tokens with transmission slot assignment toward throughput optimization. Due to the simplified scheduling based on tokens, TKN-TWN is able to provide scalability and topology adaptability. In addition, TKN-TWN allows burst transmission by leveraging the contention-free nature of TDMA, and sustains high throughput with burst data transmission when sensor nodes have similar traffic pattern. An extensive simulation study indicates that TKN-TWN achieves robust data delivery even in densely deployed large scale sensor networks. Experimental results on Tmote Sky show that TKN-TWN is able to provide throughput over 10 KByte/s, an improvement of about 23% over a prior work.

We present a design and evaluation of Choco, a low-power, end- to-end reliable collection protocol for wireless sensor networks. We construct Choco on Glossy, which is a recently presented efficient flooding scheme exploiting constructive-interference phenomena. Although Glossy is originally developed for flooding, it can be regarded as a networking primitive which provides low-power, low- delay, any-to-any communication reachability. In Choco, all packet transmissions are based on Glossy. A sink node explicitly schedules each node operation in a centralized and fine-grained manner with Glossy, and controls retransmission and power saving mode of each node. Each sensor node transmits data packets to the sink node with Glossy according to the request from the sink node. Although Choco is very simple mechanism, we reveal that Choco has considerable merits over current data collection protocols through two different testbed evaluations. Testbed evaluations demonstrate that Choco provides 14.7 times more energy-efficient collection than the state-of-the-art, while achieving end-to-end reliability for every node.

Data-intensive wireless sensor network applications, such as structural health monitoring and earthquake monitoring, require high throughput bulk data collection. Based on the fact that each node stores the same amount of sensor data, we propose a Maximum-Subtree-First Collection Protocol (MSFCP), which adopts Maximum-Subtree-First scheduling on top of multi-channel block transfer to maximize overall throughput. We present the theoretical analysis that MSFCP can achieve optimal throughput in the ideal propagation environment, and we achieve overall throughput of 135 kbps on the IRIS Mote platform.

For the efficient use of spectrum resource, it is important to understand spectrum occupancy at a high spatial resolution, so a large number of measurement locations are required. In this work, in order to increase measurement locations, we design and implement a low-end spectrum sensor which is capable of switching to different channels in a spectrum range of the UHF band. The spectrum sensor can provide intuitive knowledge for spectrum usage.

Performance of Superconducting Submillimeter-Wave Limb Emission Sounder (SMILES) onboard International Space Station was discussed from the analysis of random errors of Chlorine monoxide (ClO) in the stratosphere and mesosphere. Some lessons learned from the SMILES operation in space are discussed.

This paper presents a preambleless communication system to realize industrial wireless control networks (WCN) which are characterized by short payloads and strict real-time requirements. The reduction of the preamble is greatly beneficial for the real-time operation because the transmission time of preambles is longer than that of the short payloads. Our system is implemented on a software defined radio (SDR) platform using GNU Radio toolkit. Experiments show the packet error rate (PER) performance is close to that of the theoretical value in an AWGN (additive white Gaussian noise) environment. Demonstrations show the real-time remote control of inverted pendulums on this system.

The Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) observes vertical profiles of atmospheric minor constituents related with stratospheric and mesospheric chemical processes. The retrieved profiles contain some error originated from the response characteristics of radio spectrometers of the SMILES instrument. The on-orbit properties are necessary to be characterized and be modeled, in order to minimize the retrieval errors.

The Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) observes 03 and other minor chemical species in the stratosphere and mesosphere. Limb observation of SMILES is sensitive to the quality of the tangent altitude retrieval. To obtain better retrieval result, knowledge of initial tangent height and antenna pattern should be as precise and accurate as possible. It was concluded that initial tangent height is calculated by using ISS attitude and mirror pointing angle, and ISS position. Antenna pattern assuming 6 points moving average was applied to the retrieval and showed reasonable results.

In this paper, we present a new mathematical model based on a “Vector Space Model” and consider its implications. The proposed method is evaluated by performing several experiments. In these experiments, we classify newspaper articles from the English Reuters-21578 data set, and Taiwanese China Times 2005 data set using the proposed method. The Reuters-21578 data set is a benchmark data set for automatic text categorization. It is shown that FRAM has good classification accuracy. Specifically, the micro-averaged F-measure of the proposed method is 94.5% for English. However, that is 78.0% for Taiwanese. Though the proposed method is language-independent and provides a new perspective, our future work is to improve classification accuracy for Taiwanese.

In our previous paper, we proposed a new classification technique called the Frequency Ratio Accumulation Method (FRAM). This is a simple technique that adds up the ratios of term frequencies among categories, and it is able to use index terms without limit. Then, we adopted the Character N-gram to form index terms, thereby improving FRAM. However, FRAM did not have a satisfactory mathematical basis. Therefore, we present here a new mathematical model based on a “Vector Space Model” and consider its implications. The proposed method is evaluated by performing several experiments. In these experiments, we classify newspaper articles from the English Reuters-21578 data set, a Japanese CD-Mainichi 2002 data set using the proposed method. The Reuters-21578 data set is a benchmark data set for automatic text categorization. It is shown that FRAM has good classification accuracy. Specifically, the micro-averaged F-measure of the proposed method is 92.2% for English. The proposed method can perform classification utilizing a single program and it is language-independent.

In distributed spectrum sensing, we deploy ten thousands of sensor nodes, and a low-cost sensor node is necessary. In this work, we design the sensor node specialized in power level measurement for distributed spectrum sensing, and we discuss 3 components of the node, which are frequency range, RBW and a detector.

Radio spectrum has turned into a precious natural resource from free goods due to the rapid development of wireless communication technology. In order to efficiently utilize radio spectrum, a spectrum policy should be enough appropriate to create new industries and new technologies. From this point of view, we have developed a distributed spectrum sensing system which collects dense information of spectrum usage over large area. In this work, we discuss the requirements and the design of the distributed spectrum sensing system.

No abstract available.

Observation strategy and Digital Electronics unit of Japanese Planet-C, next Japanese Venus observation program is described and the adoptability of loss-lees data compression method, HIREW and JEPG2000 is discussed.

In this paper we present a high-density earthquake monitoring system using wireless sensor networks. For high-precision monitoring, we developed Pavenet OS, which is a hard-realtime operating system for sensor nodes, and acceleration sensor board. Sensor nodes of the system sample acceleration with less than 0.3 us jitter with Pavenet OS. The system provides earthquake engineering researchers the ability to measure vibrations of structures during earthquakes at less cost and higher node density than previous systems.

In the present paper, we consider the automatic text categorization as a series of information processing and propose a new classification technique called the Frequency Ratio Accumulation Method (FRAM). This is a simple technique that calculates the sum of ratios of word frequency in each category. However, in FRAM, feature terms can be used without limit. Therefore, we propose the use of the character N-gram and the word N-gram as feature terms using the above-described property of FRAM. Next, we evaluate the proposed technique through a number of experiments. In these experiments, we classify newspaper articles from Japanese CD-Mainichi 2002 and English Reuters-21578 using the Naive Bayes method (baseline method) and the proposed method. As a result, we show that the classification accuracy of the proposed method is far better than that of the baseline method. Specifically, the classification accuracy of the proposed method is 87.3% for Japanese CD-Mainichi 2002 and 86.1% for English Reuters-21578. Thus, the proposed method has very high performance. Although the proposed method is a simple technique, it provides a new perspective and has a high potential and is language-independent. Thus, the proposed method can be expected to be developed further in the future.

OPUS is a nadir-looking, cross-track scanning ultraviolet spectrograph, which will be boarded on NASDA's GCOM-A1 satellite (one of the first generation satellites of Global Change Observation Mission), which is proposed to be launched in the year 2007. OPUS was formerly named Ozone Dynamics Ultraviolet Spectrometer (ODUS). Recently, we have come to place importance on observation of polluted atmospheric condition as well as continuous monitoring of ozone from NASA's Total Ozone Mapping Spectrometer (TOMS) series. Consequently, we have started to study about modification of instrument specifications. Currently, OPUS takes over the specification of ODUS as it is, but according to the result of the study, OPUS might be equipped with some new features. In this paper, the latest outcomes of the study are presented.

The Ozone and Pollution measuring Ultraviolet Spectrometer (OPUS) is a satellite-borne, nadir-looking ultraviolet spectrometer for measuring total column ozone, SO/sub 2/, aerosols, NO/sub 2/, HCHO, BrO, and OClO. It will be a NASDA's core instrument of GCOM-A1 (GCOM: Global Change Observation Mission) satellite to be launched in 2007. The GCOM program is designed to determine the climate trends. The GCOM-A1 will carry the SOFIS (Solar-occultation FTS for Inclined-orbit Satellite, developed by Environment Agency of Japan), and SWIFT, which measures stratospheric wind, provided by ESA/CSA.

NASDA has been conducting an extended phase-A study on the Ozone and Pollution measuring Ultraviolet Spectrometer (OPUS), which is a nadir-looking, cross-track scanning ultraviolet spectrograph. OPUS was formerly named Ozone Dynamics Ultraviolet Spectrometer (ODUS). OPUS measures the backscattered solar radiation for the region between 306 and 420 nm with sampling step of 0.5 nm. It observes distributions of atmospheric ozone, sulfur dioxide (SO/sub 2/) and other parameters including aerosols. In this paper, (1) a feasibility of the retrieval of total column SO/sub 2/ is examined, and (2) a preliminary result on SO/sub 2/ measurement using airborne spectrograph is demonstrated.

Discusses a problem of deduction with uncertainty that has been dealt with by various diagnostic expert systems. First, we propose a mathematical framework of deductive reasoning with uncertainty. The subject of the reasoning is the calculation of conditional probabilities. Second, we establish a new reasoning method. Our deduction algorithm can compute the conditional probabilities precisely. To put it another way around, the result minimizes the divergence.

The Improved Limb Atmospheric Spectrometer (ILAS) developed by the Environment Agency of Japan was successfully flown in space on board the Sun synchronous polar-orbiting satellite ADEOS (Advanced Earth Observing Satellite) on August 17, 1996, ADEOS, with ILAS and other sensors on board, performed successfully until June 30, 1997, after which an unexpected sudden failure of the ADEOS satellite solar battery system prevented further measurements. ILAS made over 6700 measurements of the stratospheric ozone layer with the solar occultation technique, producing vertical profiles of ozone, other ozone-chemistry related gases, aerosol extinction coefficients, temperature, and pressure in the high-latitude stratosphere. The ILAS data processing software so far used was Version 3.00, and algorithm tests are currently being made for the improved Version 3.10 software which includes correction of nongas contribution due to aerosols and polar stratospheric clouds (PSCs). The present paper describes mainly the status of data processing and validation and the results of validation and comparison with other independent data sets.

Reports on the development of a geographical route planning system using uncertainty reasoning. This system searches for the route from a start point to a goal point indicated on a map. This system uses the digitized terrain map available from the Japanese Geographical Survey Institute. The target area of the route planning is subdivided into fine meshes of 100 meters square. This system is composed of two reasoning modules: a mobility cost evaluation module and a route planning module. The former module evaluates mobility costs for every 300/spl times/300 meshes included in the designated area. Domain experts often use ambiguous data interpretation knowledge for evaluating terrain circumstances and deciding the mobility cost in a mesh. We introduce two uncertainty reasoning mechanisms to represent such a data interpretation process: one is fuzzy reasoning, and the other is Dempster-Shafer theory. The route planning module uses the F* optimization algorithm. The geographical route planning system also offers knowledge editing facilities for describing the mobility cost evaluation knowledge, such as a dataflow diagram editor for designing the data integration process and a membership function editor for designing data abstraction methods. These knowledge editors facilitate the development and modification of a mobility cost evaluation knowledge base.

This communication describes a procedure to estimate the vertical profiles of stratospheric aerosols based on the visible data to be obtained by ADEOS/ILAS. The authors' algorithms mainly consist of two parts: the first process is baseline estimation for the observed transmittance spectrum, followed by the inversion process that derives vertical profiles of atmospheric extinction from ILAS transmittance data. Model calculations with an ILAS simulator show that the authors' treatment provides quick and accurate results within the expected domain of validity.>

The authors explain an integrated support environment for software maintenance. The essential feature is bridging configuration management and quality management. The environment has been successfully applied to the development and maintenance of a family of switching systems for several years.>