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The comprehensive relationship between meteorological conditions and whether low water cloud touches the surface, particularly at sea, is examined with the goal of improving low-cloud detection by satellite. Gridpoint-value data provided by an operational mesoscale model with integration of Multifunction Transport Satellite-2 data can provide sufficient data for statistical analyses to find general parameters that can discern whether low clouds touch the surface, compensating for uncertainty due to the scarcity of observation sites at sea and the infrequent incidence of fog. The analyses reveal that surface-touching low clouds tend to have lower cloud-top heights than those not touching the surface, although the frequency distribution of cloud-top height differs by season. The bottom of the Γ > Γm layer (where Γ and Γm are the vertical gradient and the moist-adiabatic lapse rate of the potential temperature, respectively) with surface-touching low-cloud layers tends to be very low or almost attached to the surface. In contrast, the tops of low-cloud layers not touching the surface tend to occur near the bottom of the Γ > Γm layer. Mechanisms to correlate these meteorological conditions with whether low clouds touch the surface are inferred from investigations into the vertical structure of equivalent potential temperature. These results indicate that the temperature difference between cloud-top height and the surface can be an appropriate parameter to infer whether low clouds touch the surface. It is also suggested that only a little addition of meteorological ancillary data, such as the forecast sea surface temperature, to satellite data allows successful performance of the discrimination.

Rainfall is one of main causes of floods. Monitoring of the rainfall is essential for understanding flood mechanism and early warning. Ground-based rain gauge is a conventional device to measure rainfall amount and considered as a point measurement. Satellite-based rainfall estimates provides complement measurement over wide area having few or even no in situ data. This study evaluates rainfall intensity variation and patterns preceding flood events in Indonesia for the period of 2003-2010 using the GSMaP_MVK satellite-based rainfall product with one hour and 0.1o x 0.1o resolutions and rain gauge station data as a benchmark. The analysed data are 3-hourly average and daily accumulation time steps. The chosen research locations were Medan City, Pekanbaru City, Indragiri Hulu Regency, Samarinda City and Manado City. Graphical comparisons of the GSMaP_MVK with the rain gauge data show discrepancies in capturing rainfall events and intensity. The GSMaP_MVK performs underestimation for the most areas, except Samarinda City, which is overestimated. Short-term period rainfall pattern is the most frequent occurred preceding flood events for the entire study areas which indicate that the areas are more susceptible to flash floods and river overflows. Overall, the GSMaP_MVK product provides promising potentiality for the application of monitoring rainfall conditions preceding flood events over the research locations. Statistical verifications reveal that on average, correlation coefficients are (0.22-0.54) and (0.65-0.83) for 3-hourly and daily scale, respectively. While, probability of rain detections (PODs) are (0.57-0.75) and (0.93-0.99), accordingly.

A simple and practical scheme for low cloud detection at sea based on geostationary weather satellite data is proposed. The scheme consists of several threshold discrimination tests, and time-consuming procedures are eschewed in order to enable near-real-time analysis. This scheme also minimizes the use of data other than from geostationary weather satellites, leading to a convenient low cloud detection procedure without ancillary data. Careful investigation of the radiative properties of low water clouds from radiative transfer simulation and satellite observations enables full utilization of the characteristics of satellite data and realization of the simple scheme. The threshold values, which should possess high generality, for the discrimination tests are obtained from statistical comparisons of Multi-function Transport Satellite-2 data to grid point value data, which allows for extensive data collection and eliminates the localities and anomalies. Verification by comparisons with radiosonde and lidar on satellite suggests that results obtained from the proposed low cloud detection scheme are reasonable.

Plasma synthetic jet actuator (PSJA) is a flow control device which has structure that insulator is tucked with electrode pair. It generates electrohydrodynamic (EHD) effect and induces a flow. The experiment was held to investigate the effect of flow control using extremum seeking with PSJA placed on the surface of NACA0012 wing installed in the wind tunnel. Frequency of the input signal to PSJA is modulated to maximize the effect of PSJA in flow control. The wake velocity fluctuation is one of indexes on separation control effect. The wake velocity is minimized over the input frequency by employing extremum seeking. The seeking algorithm calculates the correlation of the modulation frequency and wake velocity fluctuation. The modulation signal frequency where the correlation changes from negative to positive minimizes the wake velocity fluctuation. To detect a local minimum of the wake velocity fluctuation by extremum seeking, it is necessary to change the modulation signal frequency with time. Sine and square waves change the modulation signal frequency to PSJA. The wind tunnel speed was changed as an external factor. The experimental results show that the modulation signal frequency can track the optimum value when the wind tunnel speed is changed. This paper shows that adaptive flow control to optimize the modulation signal frequency with PSJA using extremum seeking enables to suppress turbulence on the flow field of wings.

One of the useful ways to measure the effect of the flow control devise is to use the wall-shear stress sensor to measure the wall-shear stress directly. The sensor used in this paper measures the wall-shear stress, which is influenced by the flow control devise. In this paper, the wall-shear stress of the plane shear layer with the plasma synthetic jet actuator (PSJA) is investigated. PSJA is a flow control device composed of electrodes with A.C. signal. The actuator uses electrohydrodynamic (EHD) effect and induces flow around the electrodes. PSJA has great advantage such as miniaturization, maintenance free, and easy to control compared to other actuators. In this paper, the wall-shear stress of plane shear layer in a low-speed turbulent wind tunnel is observed to measure the effect of the PSJA. The results show that the PSJA changes the flow condition of shear layer by accelerating the flow in shear layer. The wall-shear stress reduces and increases according to the displacement of the wall-shear stress sensor and the actuator.

Recent years, there are researches to operate vehicles by the voice instruction. It is important for these researches to recognize a peripheral environment. There are internal sensor and external sensor used to recognize a peripheral environment. Internal sensor is often used together with external sensor because the error with driving system is caused. Imaging sensor can especially measure the plane compared with other external sensors, the research combined with internal sensor is abundant. The delay is caused because it takes the processing time when imaging sensor is used. In this research, imaging sensor is installed on the vehicle, so the system is visual feedback control. State-space database is used to control the vehicle in this study. The vehicle can run on the straight corridor without the patterns like joint of the building. The vehicle cannot distinguish the patterns like joint of building on straight corridor and wall because same kind of feature appears to the objects. As result, the vehicle can be controlled regardless of the patterns like joint of the building on straight corridor. The state quantity of state-space database that solves this problem is found.

This paper describes humidity characteristics of Plasma Synthetic Jet Actuator (PSJA). PSJA is flow control device using the Electro Hydro Dynamic (EHD) effect of the glow-discharge. PSJA can be downsized, controlled easily, and has quick control response. Though the flow control around an airfoil with PSJA is mainly studied, its characteristics have not been clarified. So, it is necessary to investigate humidity characteristics of induced flow by PSJA. In this paper, the induced flow from PSJA was measured in the different relative humidity. The experimental results show that the effect of induce flow by PSJA had decreased with increase relative humidity. Therefore, when PSJA was used, relative humidity becomes an important parameter.

This paper presents an investigation of PWM control with plasma synthetic jet actuator (PSJA). PSJA is an electric device designed for flow control using electrohydroninamic (EHD) effect. PWM control (ON-OFF control to glow discharge periodically) was proposed to induct waves which are subjected to lower frequencies than the frequency to drive the PSJA. The results show that the decrease of drag such as maximum velocity deficit and RMS has dropped by selecting a proper frequency in an angle of attack 15°, where the decrease of drag wasn't observed without PWM control. The result has indicated that the most effective frequency exists for separation control with PWM.

Flow on an airfoil was investigated with plasma synthetic jet actuator. Plasma synthetic jet actuator is a flow control device, which is composed of two electrodes with a.c. signal, using electrohydrodynamic (EHD) effect and induces flow around the electrodes. Plasma synthetic jet actuator has some important advantages ; for example, miniaturization is possible, mechanical maintenance is almost free. Therefore it is expected to apply for flow control around an airfoil. In this study, to observe behavior of the plasma synthetic jet actuator, experimental study was conducted. A NACA0012 airfoil, in which plasma synthetic jet actuator is embedded, was chosen, and the wake velocity behind airfoil is measured by hot wire anemometer with or without operating the actuator.

This paper presents investigation of optimum location of plasma synthetic jet actuator (PSJA) that is an electric device designed for flow control around an airfoil using electrohydrodinamic (EHD) effect. New turbulence model, that is, “pseudo viscosity model” is proposed to describe effect of PSJA in N-S simulation, witch is aimed to achieve low computational cost. Computational result qualitatively agrees with experimental one about wake velocity profile of wing. Next, separation delay control with another type of PSJA is simulated. Knowledge obtained from present simulations about optimum location of PSJA also agress with it obtained from experiments stretch several years.

In this paper, the stabilization problem of a plant with known delay in observation is studied. Although several methods, the Smith predictor or the state predictive control, have already been proposed about the control of plant with time delay, theoretical limitations and the practical inconvenience were left to be solved; e. g., the Smith predictor can only treat the stable systems, and the numerical integration of the exponential function is difficult in the state predictive control. The presented method combines the state feedback control with the delayed feedback control, which can stabilize the unstable systems and can be easily performed. The numerical simulation of the stabilization of the serial double inverted pendulum shows that the proposed method can he applied to stabilization of the unstable system and is effective for the impulsive disturbance.

In recent years, speech-recognition technology progresses dramatically, and it has already been used for word processors etc. If this speech-recognition technology is used for operation of an electric wheelchair, an electric wheelchair is thought to be a useful vehicle for a physically handicapped person who has a trouble especially in hand. However, continuous operation cannot easily be performed by voice instructions, so operativity is not good. In this research, in order to solve this problem, automatic operation by visual feed back control was proposed, and we improved operativity of voice controlled vehicles.

Flow induced by plasma synthetic jet actuator (PSJA) is investigated using computational fluid dynamics. PSJA is a flow control device and induces flow using electrohydrodinamic (EHD) effect around electrodes exerted AC voltage. Its mechanism is not well known, but it is said that paraelectric force proportioned to gradient of electric energy density is important on PSJA. In this paper, numerical simulation is documented to discuss mechanism of PSJA with considering only paraelectric force as EHD effect. The numerical results agrees with flow pattern observed on experiments. The difference between two types of PSJA, that is, directed type PSJA and non-directed one is indicated.

This paper presents a new method, namely pseudo-viscosity particle model for numerical simulation on flow control using plasma synthetic jet actuator (PSJA). Using the method, effect of PSJA is added to Navier-Stokes equation as an appearance viscosity in addition to turbulent eddy viscosity computed from LES, and its influence is traced as Lagrangian particles start from position of PSJA. The appearance viscosity caused PSJA is named pseudo-viscosity. Result of simulation using our model is compared with experimental result about a flow around NACA0012 airfoil with PSJA when angle of attack is 0 and 7 degrees, and agreed qualitatively on profile of streamwise velocity defect on wake. We also suggest there is some possibility that PSJA reduce effect of turbulent eddy viscosity.

Numerical experiments were conducted to examine applicability of Pyragas' Delayed feedback (DFB) control theory for active control of the coupled map lattice (CML). CML is known as a simple model with the essential feature of spatiotemporal chaos. Assuming spatiotemporal chaos reprsents wall turbulence, DFB control theory was applied to examine possibility of active control of turbulence. Notable feature of this study is that DFB control units are distributed to each non-linear element of CML. Since each control unit works independently, the control algorithm is simple and applicability to a real system is promising. Simulation results show that the present method can stabilize the whole CML, even though only 20% of the lattice or the non-linear elements were controlled by DFB method.

Active control of jets emitted into a two-dimensional channel with insulated suction near the wall during monitoring with a neural network is described. The aim of this work is to simulate the possibility of controlling the flow pattern with a flip-flop phenomenon by suitable suction. In this case, the output of a neural network is estimated satisfactorily based on 3 flow patterns of teaching data. The periodic flow pattern at the Reynolds number Re =1.0x10 3 is reduced by a suction rate of less than 10% for primary jets. Then flow becomes stable as a result of feedback gain of the neural network. Since the control with suction need not be continuous, the power cost is reduced. The nonperiodic case at Re =1.0x 10 4 is difficult to control, but we achieved good control by with the use of a suitable suction rate with the neural network.

A new method for estimating convection using a incompressible Navier-Stokes solver is presented. A least squares identification method was applied to obtain derivatives around a reference point. Higher order derivatives were also utilized in order to reduce artificial diffusivity caused by firstorder upwinding. An iterative method similar to SMAC (simplified marker and cell) was used for time marching, and least squares estimation was carried out to determine predictors of variables. Therefore, the estimation time can be neglected in the entire calculation. Flow around a cylinder and two-dimensional cavity flow were selected to examine the applicability of the current method. Static pressure distribution and velocity profiles agree fairly well with previously obtained data. However, it was found that artificial viscosity is not negligible, even if higher order derivatives were utilized.

The 5-equation model which represents weakly nonlinear two-dimensional thermal convection with various boundary conditions at the top and bottom walls has been constructed. Although the present system includes two control parameters of competing instabilities, the second parameter is fixed at unity, since the aim of this work is to obtain a model which is realistic compared with the Lorenz model but which maintains comparable simplicity. Examination of bifurcation structures of the present model obtained by increasing Rayleigh number as a parameter shows that there is a definite range of parameters in which the structures of orbits are strongly dependent on the boundary conditions such as slip/slip, slip/no-slip and no-slip/no-slip at respective top/bottom walls. In particular, a unique pattern for an inverse transitional region, which seems to be a "twin period-doubling bifurcation, " has been found for the first time in the case of no-slip/no-slip conditions.