The traveling wave type antenna generally uses an element of several times of the wavelength. However, by using the dipole antenna with resistive loading, the traveling wave can be generated even if the element of the half-wavelength is used. This type of anntena has a simple structure, and works as a small traveling wave antenna having a broadband characteristic. This paper presents an analysis of two kinds of antennas utilizing the characteristics of this traveling wave antenna. For the analysis of the antennas, the moment method is used, and the loading resistance value on the element can be calculated by the function minimization method. The results show that the dipole antennas with resistive loading have single directivity and can be occurred the circularly polarized wave by changing its element shape. In addition, the antennas optimized for Ground-penetrating radars(GPR) was investigated based on the result.

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 We propose a new method to estimate a 2D detail temperature distribution in the ocean from seismic data. This method is based on a combination of Simulated Annealing (SA) and fast waveform calculation methods. In contrast to the local optimization methods, the SA enables us to optimize the model parameters with less dependency on the initial model. We applied this inversion method to multi-channel seismic reflection data acquired around the axis of Kuroshio Current. Since the survey line was oriented NW-SE direction, we can obtain the velocity / temperature structure across the Kuroshio Current using the seismic data. The 2D acoustic velocity structure derived from the inversion revealed that the multi-layered structures are dominant in the ocean, and these layers are dipping toward the current axis. We estimated the temperature distribution from the obtained acoustic velocity using an empirical formula. Furthermore, we investigate the effect of random noise on the inversion results. We contaminated the data derived from the finite difference method by Gaussian distributed noise. We observed that the estimated velocity contrasts tend to get large compared to the true contrasts as S/N ratio decreases. This suggests that one of the reasons for the large velocity contrasts in the obtained acoustic velocity profiles could be originated from the observation noises.

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 In this study, the coefficients of SPAC and CCA methods that are, i. e., two principle correlation methods using microtremor are formulated for multi mode case based on a logical consequence of the working hypothesis: Seismic Interferometry that foresees that the power-partition ratio among the normal modes of Rayleigh waves is described by their eigen function that controls amplitude of their elastodynamic Green's function. Then, two examples of the numerical validation check are shown for application of the dual mode inversion targeted on the dispersion curve of Rayleigh waves determined by these correlation methods. A gradual migration of the theoretical dispersion curves based on the power partition ratio is allowed from the fundamental mode to the first higher one and vice versa as well as the jump from one mode to another depending on their amplitude. First experiment shows that the application of the single mode inversion to the dispersion curve theoretically calculated based on the power partition ratio results in the misinterpretation: a shallower velocity discontinuity with a higher velocity than those of the given velocity structure and that this discrepancy is solved by using the dual mode inversion mentioned above. In the second experiment the dispersion curve obtained by applying SPAC method to the computer simulated waveform data of microtremor is fitted well with the theoretical curve based on the power partition ratio mentioned above and that the dual mode inversion gives a velocity structure much more similar to the model structure than that given by the single mode inversion. These support the advantage of the dual mode inversion in comparison with the single mode one and also the appropriateness of Seismic Interferometry.

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 One of the major issues in disposal of nuclear waste is that the long term behaviors of sedimentary soft rocks can be affected by various environmental factors such as temperature, mechanical conditions or hydraulic conditions. Therefore, it is necessary to develop a method for evaluating the long term stability of caverns in sedimentary soft rocks as subjected to changes of environment. We have conducted in-situ heating test to evaluate the influence of high temperature to the surrounding rock mass at a depth of 50m.
 The well with a diameter of 30cm and 60cm of height, was drilled and filled with groundwater. The heater was installed in the well for heating the surrounding rock mass. During the heating, temperature and deformation around the well were measured. To evaluate the influence of heating on sedimentary soft rocks, it is important to monitor the extent of heated area. Resistivity monitoring is thought to be effective to map the extent of the high temperature area. So we have conducted resistivity tomography during the heating test.
 The results demonstrated that the resistivity of the rock mass around the heating well decreased and this area was gradually expanded from the heated area during the heating. The decreasing rate of resistivity on temperature is correlated to that of laboratory experimental result and existing empirical formula between aqueous solution resistivity and temperature. Resistivity is changed by many other factors, but it is expected that resistivity change by other factors is very few in this test. This suggests that high temperature area is detected and spatial distribution of temperature can be mapped by resistivity tomography. So resistivity tomography is expected to be one of the promising methods to monitor the area heated by nuclear waste.

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 Resistivity survey and measurement of groundwater conductivity were performed in 2003 and 2004, to investigate the distribution of fresh and salt groundwater in the Yellow River Delta where due to rapid increasing of river sedimentation and over irrigation, water environment problems such as temporary zero-flow of the river occur. Radiocarbon dating analysis of groundwater samples from this region was also carry out to indicate origination of groundwater. Results show that fresh groundwater distributes in the southern part of this region and salt groundwater in the other part. Radiocarbon dating analysis reveals that there are three origin of groundwater in this region. First one is that the salt water are enveloped by sedimentation of the sand from Yellow River in the coastal zone, second one is that the paleo-saltwater that passes the concentration remains in the center of the delta, and third one is that the fresh water flowed from the inland exists in the south area.

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