In this paper, we estimated life cycle inventories (energy intensities and CO2 emissions) on the biomass gasification CGS, Bio-H2, Bio-MeOH (methanol) and Bio-DME (di-methyl ether), using the bottom-up methodology. CO2 emissions and energy intensities on material's chipping, transportation and dryer operation were estimated. Also, the uncertainties on the moisture content of biomass materials and the transportation distance to the plant were considered by the Monte Carlo simulation. The energy conversion system was built up by gasification through the BLUE Tower process, with either CGS, PSA (Pressure Swing Absorption) system or the liquefaction process. In our estimation, the biomass materials were the waste products from Japanese Cedar. The uncertainties of moisture content and transportation distance were assumed to be 20 to 50 wt.% and 5 to 50 km, respectively. The capability of the biomass gasification plant was 10 t-dry/d, that is, an annual throughput of 3,000 t-dry/yr. The production energy in each case was used as a functional unit. Finally, the energy intensities of 1.12 to 3.09 MJ/MJ and CO2 emissions of 4.79 to 88.0 g-CO2/MJ were obtained. CGS case contributes to the environmental mitigation, and Bio-H2 and/or Bio-DME cases have a potential to reduce CO2 emissions, compared to the conventional ones.
In order to design optimal biomass utilization system for rural area, OMNIBUS (The Optimization Model for Neo-Integrated Biomass Utilization System) has been developed. OMNIBUS can derive the optimal system configuration to meet different objective function, such as current account balance, amount of biomass energy supply, and CO2 emission. Most of biomass resources in a focused region e.g. wood biomass, livestock biomass, and crop residues are considered in the model. Conversion technologies considered are energy utilization technologies e.g. direct combustion and methane fermentation, and material utilization technologies e.g. composting and carbonization. Case study in Miyakojima, Okinawa prefecture, has been carried out for several objective functions and constraint conditions. Considering economics of the utilization system as a priority requirement, composting and combustion heat utilization are mainly chosen in the optimal system configuration. However gasification power plant and methane fermentation are included in optimal solutions, only when both biomass energy utilization and CO2 reduction have been set as higher priorities. External benefit of CO2 reduction has large impacts on the system configuration. Provided marginal external benefit of more than 50,000 JPY/t-C, external benefit becomes greater than the revenue from electricity and compost etc. Considering technological learning in the future, expensive technologies such as gasification power plant and methane fermentation will have economic feasibility as well as market competitiveness.
This paper evaluates characteristics of two kinds of power generation systems utilizing fermentation gas of municipal refuse which is generated with use of a fermentation equipment of sorted refuse from ordinary collected garbage. In evaluation, a garbage incineration plant treating refuse of 100 t/d was adopted. The two systems investigated are the following systems: (a) gas engine power generation system (Sys-GE) and (b) steam turbine power generation system with super heater of steam (Sys-SH). The characteristics of two systems have been estimated together with the conventional steam turbine power generation system (Sys-C). It has been estimated that Sys-GE and Sys-SH has 2.11 and 2.55 times greater energy saving and CO2 reduction effect compared with Sys-C, respectively.
The expansion of the renewable energy introduction is examined as measures for controlling global warming. Wind power generation is expected as effective power resource, but the negative impact from the difficulty of an unstable output is concerned. In recent years, WT generation with contract of cut-of with shorting adjusting power and with rechargeable battery for stabilizing control are examined, but the introduction has not been accelerated yet because there is an influence in WT generation entrepreneur's business. In this paper, we make a brief summary of relation between the fluctuation of wind power generation and stability of electric power operation, and two types of approach; cut-off contract and stabilization using rechargeable battery. For the stabilization using battery, there are two methods, one is reduction control and the other is constant control. We propose a new control method for constant control based on profit optimization considering WT generation forecast and its risk of deviation. We also propose the estimation method for the .limitation of battery installation. Simulation results show the efficiency of our proposed methods.
When the target capacity of PV systems toward 2030 is realized, most of newly constructed houses may have a PV system. In such the situation, PV systems can contribute to electricity supply in the emergency situation as well as ordinary situation. This paper focuses on an emergency microgrid consisting of residential PV systems and battery system for the electricity supply to a load center during urban disaster or massive blackout. Considering a typical urban residential area of 500m×500m and a typical irradiation pattern, we calculated the available electricity from PV systems and the required capacity of battery for compensating for the shortage of electricity from PV systems. If the weather condition is fine, the total electricity supply from PV systems would be much larger than the restricted electricity demand during urban disaster, resulting in the battery recharged with the surplus electricity from PV systems. Therefore, if we install the battery system capable for electricity supply during one night, the emergency microgrid can meet the electricity demand during the most combinations of continuous three days in a year. Then, assuming that the emergency microgrid is formed in each 500m×500m area or 1km×1km area, we statistically evaluated the feasibility of emergency microgrid in Aichi prefecture. The result shows that if we can install the battery with the total capacity of 1500 MWh, the emergency microgrid can be applied in many residential areas for some million people those who may have black-out after the strong earthquake which may happen in Tokai area.
We have proposed a method to evaluate the kW-value of PV system, where the kW-value is calculated as an average value of reduction in peak electricity load on the electric power utility among a few days with large peak load in a year. By using the proposed method, this paper discusses the difference in kW-value of PV system due to the difference in region considered. The evaluation is based on the actual insolation data in 45 points throughout Japan and electricity load on the electric power utility both observed in the 1990's. As results, the number of days with large reduction in peak load by PV systems is larger in Western Japan, because the solar noon is slightly late in Western Japan, resulting in the large electricity supply of PV system during the period of large electricity load. Therefore, when the kW-value is evaluated based on a number of days with large daily peak load, the kW-value of PV system would be higher in Shikoku and Kyusyu regions. However, when the kW-value is evaluated based on a number of days with large daily peak demand but with small insolation, the evaluated kW-value is not so different among regions in Japan, because the ratio of such the day is not so different among regions.
We fabricated hybrid complementary inverters with n-channel zinc oxide (ZnO) transistors as the n-type inorganic material and p-channel organic transistors using pentacene as the p-type organic material. The complementary inverter exhibited a large voltage gain of 10-12 and a cut off frequency of 0.5 kHz. ZnO thin film transistors show n-type semiconducting properties having field effect mobility of 2.1×10-3 cm2/Vs. On the other hand, pentacene thin film transistors show p-type semiconducting properties having field effect mobility of 3.2×10-2 cm2/Vs. We describe basic charge transfer characteristics of ZnO thin films. The results obtained here demonstrate that it is important for the transistor using ZnO to be injected charge from electrode to semiconducting material effectively.
Multi-digit multiplication is widely used for various applications in recent years, including numerical calculation, chaos arithmetic, primality testing. Systems with high performance and low energy consumption are demanded, especially for image processing and communications with cryptography using chaos. Karatsuba algorithm with computational complexity of O(n1.58) has been employed in software for multiplication of hundreds to thousands bits, where n stands for bit length of operands. In this paper, hardware design of multi-digit integer multiplication based on Karatsuba algorithm is described and its VLSI realization is evaluated in terms of the cost, performance, and energy consumption. We present two design choices of the Karatsuba hardware: RKM (Recursive Karatsuba Multiplier) and IKM (Iterative Karatsuba Multiplier). We found that RKM has less area cost than WTM (Wallace Tree Multiplier) for bit length larger than 29 with area cost of 30mm2. Critical path delay of RKM is always larger than that of WTM. Therefore, we should use WTM as combinational circuits for IKM to have better cost performance. We also found that a version of IKM using 0.18μm process can perform 1024-bit multiplications 30 times faster than software at the area cost of 10.9mm2. Energy for the computation by the IKM version was found to be nearly 1/600 of that consumed by general purpose processor which executes the software. The results obtained by this study will help system designers for applications requiring multi-digit multiplication to select design alternatives including ASIC realization.
In this paper, a new modulation scheme, Pulse-position Multi-Pulse Modulation (PMM) which is a combination of MPM (Multi-Pulse Modulation) and PPM (Pulse Position Modulation), has been proposed in order to increase the total data rate and improve the error performance. By this scheme, the data-modulated pulse can be used for transmitting more than one bit data depending on the level of modulation. Moreover, the error performance has been improved because for the same Eb/N0, the energy per pulse has increased. In addition, the multiple access performance of the proposed system has been improved because of more transmitted data bits per pulse. The simulation results show that the total throughput performance of the proposed system has been improved, nearly 5-6 times when compared to the conventional TR-UWB communication system. Because of the higher data rate with a good error performance, the proposed system should be one of good candidates for high data rate communication system.
A human being understands the objects in the environment by integrating information obtained by the senses of sight, hearing and touch. In this integration, active manipulation of objects plays an important role. We propose a method for finding the correspondence of audio-visual events by manipulating an object. The method uses the general grouping rules in Gestalt psychology, i.e. “simultaneity” and “similarity” among motion command, sound onsets and motion of the object in images. In experiments, we used a microphone, a camera, and a robot which has a hand manipulator. The robot grasps an object like a bell and shakes it or grasps an object like a stick and beat a drum in a periodic, or non-periodic motion. Then the object emits periodical/non-periodical events. To create more realistic scenario, we put other event source (a metronome) in the environment. As a result, we had a success rate of 73.8 percent in finding the correspondence between audio-visual events (afferent signal) which are relating to robot motion (efferent signal).
We have studied a man-machine interface system by using an eye gaze detection technique. Target users for this system are ordinary people and orthopedically impaired people who have no movement in their hands and heads. Ordinary people can use this system under the condition that they do not move their heads. An algorithm for detecting the center of the iris is proposed in this paper. An image of the eye is captured with a small video camera and the center of the iris is obtained by filtering in color space and pattern matching with a ringshaped template. Improvement of the pattern matching speed is also described and the effectiveness of the reduction of calculation costs is shown in the paper. Furthermore, the accuracy of the eye gaze detection was evaluated.
Speckle effects are commonly observed in synthetic aperture radar (SAR) images. The human eye is capable of deriving meaningful information from SAR images; however, an automatic or semi-automatic processing algorithm has difficulty in distinguishing objects in the images because of noise effects present in those images. This paper presents a segmentation method for SAR images, which employs an anisotropic diffusion algorithm. In the proposed scheme, a SAR image is transformed into a logarithmic domain where the diffusion process is used to grow homogeneous regions in the noise environment until the regions reach some criteria for homogeneity; consequently, the segmented image in the logarithm domain is converted to the intensity domain by an exponential function. To grow homogeneous regions the adaptive diffusion method is introduced with a tensor technique in which tensor data are varied with the neighboring pixels. The diffusion algorithm will stop itself by a standard deviation divided by the mean, which is provided according to the homogeneity criteria. Results are shown on both synthetic and satellite SAR images. The evaluation of the proposed method employs the theoretical gain of equivalent numbers of looks (ENL).
The presentation of the travel time information to drivers is one of the important roles of the information system concerned with road traffic. This paper proposes a prediction method of the travel time in urban district using the travel time data of the small section which constitutes a route. The forecasting model consists of past time series data about the travel time of the small section. The travel time and accuracy of a near future of the route are estimated using State Equation of the forecasting model. The validity of the method is verified using real data. As the results of examinations, the prediction error became almost 2.5 minutes. Generally, to fifty minutes of travel time, it is desirable that prediction error is within five minutes. Therefore, it is conceivable that this result is fit to sufficient practical use.
This paper discusses a design problem of robust stabilization for a class of uncertain switched linear systems via variable gain controllers. The uncertainties under consideration are supposed to satisfy the matching condition, and switchings among subsystems are determined by using the nominal system. The proposed robust stabilizing controller consists of a switching rule, a state feedback law with a constant gain matrix and a state feedback law with a variable gain matrix tuned by adjustable parameters. In this paper, we show a design method of the switching rule, the feedback gain matrices and the adjustment law of the adjustable parameter. Finally, numerical examples are presented to demonstrate the effectiveness of the proposed robust stabilizing controller.
This paper deals with control of dynamic visual feedback systems with a movable camera configuration. This configuration consists of a robot manipulator and a camera that is attached to the end-effector of another robot manipulator. This system which can be interpreted the dynamic visual feedback system with an eye-in-hand configuration and a fixed camera one as a special case, can enlarge the field of view. Firstly the dynamic visual feedback system with an eye-to-hand configuration is given with the fundamental representation of a relative rigid body motion. Secondly we construct the dynamic visual feedback system with a movable camera configuration by combining the camera control error system. Next, we derive the passivity of the dynamic visual feedback system. Based on the passivity, stability and L2-gain performance analysis are discussed. Finally the validity of the proposed control law can be confirmed by comparing the experimental results.
Acording to the principle of Bode, there is the minimum-phase state as the output of minimum-phase function in the controlled object. In this paper the minimum-phase state observer/control system is shown to have abilities for optimality and robustness. The assignment of zeros in the characteristic polynomials wwD(s) and f0(s) are chosen for the design of optimality and robust stability, corresponding to the additive characteristic deviation anticipated for the controlled object. Numerical example shows the minimum-phase state observer/control system can be optimal and also restrain the deviation from unstability.
This paper extends a fuzzy version of Analytic Hierarchy Process to reflect human's vagueness or subjective judgment. New comprehensive technique, variable axis method [VAM], is developed to decide the total ordering of fuzzy numbers. Further, we adopt the fuzzy optimization method in group decision-making, minimizing the total sum of the dissatisfaction of each evaluator. Geometric mean technique is employed to synthesize a fuzzy positive reciprocal matrix. Numerical example demonstrates the effectiveness and the applicability of the proposed decision making model.
In this paper, we propose smooth risk communication support method in Multiplex Risk Communicator. In advanced information society, various information, various social risk and various complicated social problem exist. Risk communication is necessary to solve complicated social problem between stakeholder with different knowledge and different standard about risk. In this paper, we introduce portal system that assists participant, to get optimal combination of counter measures for participant. The characteristics of the proposed method are, first to classify information acquisition stage of participant, second to enable smooth change of information acquisition stage, third to support information acquisition by offering information portal.
Golomb-Rice coding is a well-known compression algorithm for sensor data. When time-series data changes drastically with the large amplitudes such as a pulse signal, the code length based on Golomb-Rice coding becomes very long. In order to shorten the code length, amplitude of signal is decreased by calculating differential signal between a raw signal with a similar signal. In this paper, we develop a lossless compression method for time-series data such as sensor data. In traditional methods, finding the past-signal from which a differential signal with low amplitude can be generated is the main topic. However, if there are no past-signals to reduce sufficiently the amplitude of differential signal, the data compression procedure takes only low effects. In our approach, a signal which decreases energy of a pulse signal or increases energy of the neighboring signal of a pulse signal is adopted to generate differential signals. In order to select an effective signal, we propose a method for detecting reference signals based on cumulative distribution features of time-series data. As results of experiments, we confirm that our proposed method can generate codes whose length is shortened. The code length was decreased to 97% on average and up to 81% in comparison with the traditional method.
This letter describes a method for reducing moiré in a captured image of LCD display. Moiré often appears in a shot image by a CCD camera because of the interference between CCD cells and luminescence devices. The method uses two images with the just focused and the off-focused. Through FFT, only moiré patterns are removed without blurring the contour of an uneven area defect in LCD display. The experimental result showed that the moiré was almost removed by the proposed method.