Noise suppression using optimum filtering of OCs generated by a multiport encoder/decoder

We propose a novel receiver configuration using an extreme narrow band-optical band pass filter (ENB-OBPF) to reduce the multiple access interference (MAI) and beat noises in an optical code division multiplexing (OCDM) transmission. We numerically and experimentally demonstrate an enhancement of the code detectability, that allows us to increase the number of users in a passive optical network (PON) from 4 to 8 without any forward error correction (FEC)

N-soliton solutions to the DKP equation and Weyl group actions

We study soliton solutions to the DKP equation which is defined by the Hirota bilinear form, {\begin{array}{llll} (-4D_xD_t+D_x^4+3D_y^2) \tau_n\cdot\tau_n=24\tau_{n-1}\tau_{n+1}, (2D_t+D_x^3\mp 3D_xD_y) \tau_{n\pm 1}\cdot\tau_n=0 \end{array} \quad n=1,2,.... where $\tau_0=1$. The $\tau$-functions $\tau_n$ are given by the pfaffians of certain skew-symmetric matrix. We identify one-soliton solution as an element of the Weyl group of D-type, and discuss a general structure of the interaction patterns among the solitons. Soliton solutions are characterized by $4N\times 4N$ skew-symmetric constant matrix which we call the $B$-matrices. We then find that one can have $M$-soliton solutions with $M$ being any number from $N$ to $2N-1$ for some of the $4N\times 4N$ $B$-matrices having only $2N$ nonzero entries in the upper triangular part (the number of solitons obtained from those $B$-matrices was previously expected to be just $N$).Comment: 22 pages, 12 figure

Cosmic Star Formation Activity at z=2.2 Probed by H-alpha Emission Line Galaxies

We present a pilot narrow-band survey of H-alpha emitters at z=2.2 in the Great Observatories Origins Deep Survey North (GOODS-N) field with MOIRCS instrument on the Subaru telescope. The survey reached a 3 sigma limiting magnitude of 23.6 (NB209) which corresponds to a 3 sigma limiting line flux of 2.5 x 10^-17 erg s^-1 cm^-2 over a 56 arcmnin^2 contiguous area (excluding a shallower area). From this survey, we have identified 11 H-alpha emitters and one AGN at z=2.2 on the basis of narrow-band excesses and photometric redshifts. We obtained spectra for seven new objects among them, including one AGN, and an emission line above 3 sigma is detected from all of them. We have estimated star formation rates (SFR) and stellar masses (M_star) for individual galaxies. The average SFR and M_star is 27.8M_solar yr^-1 and 4.0 x 10^10M_solar, respectivly. Their specific star formation rates are inversely correlated with their stellar masses. Fitting to a Schechter function yields the H-alpha luminosity function with log L = 42.82, log phi = -2.78 and alpha = -1.37. The average star formation rate density in the survey volume is estimated to be 0.31M_solar yr^-1Mpc^-3 according to the Kennicutt relation between H-alpha luminosity and star formation rate. We compare our H-alpha emitters at z=2.2 in GOODS-N with narrow-band line emitters in other field and clusters to see their time evolution and environmental dependence. We find that the star formation activity is reduced rapidly from z=2.5 to z=0.8 in the cluster environment, while it is only moderately changed in the field environment. This result suggests that the timescale of galaxy formation is different among different environments, and the star forming activities in high density regions eventually overtake those in lower density regions as a consequence of "galaxy formation bias" at high redshifts.Comment: Accepted for publication in PASJ Subaru Special Issue, 11 pages, 10 figure

Basis Risk and Low Demand for Weather Index Insurance

Natural Resource Economics Discussion Papers are preliminary research reports by members of the GSA-NRE Kyoto University circulated for comments and suggestions. They have not been externally peer-reviewed or been subject to the review by the editorial board.Basis risk --an imperfect correlation between an aggregate index and idiosyncratic crop damage-- has been widely recognized as a major impediment to embracing index insurance. However, empirical evidence is still scarce because of the difficulty in its direct measurement. In this study, we estimate the impact of the basis risk on demand for a rainfall index insurance product using household survey data from rural Zambia. First, we develop a simple model of insurance demand to motivate our econometric specifications. Then, we quantify the basis risk for each surveyed household with past rainfall data at the plot-level. Exploiting changes in insurance design across years, we use within-household variations in the basis risk to estimate its impact. Empirical results illustrate that the basis risk has significant and adverse effects on insurance demand. Despite its statistical significance, our results also suggest that minimizing the basis risk would not yield enough economic benefits to offset the associated costs

Enhanced Star Formation of Less Massive Galaxies in a Proto-Cluster at z=2.5

We investigate a correlation between star-formation rate (SFR) and stellar mass for Halpha emission line galaxies (HAEs) in one of the richest proto-clusters ever known at z~2.5, USS 1558-003 proto-cluster. This study is based on a 9.7-hour narrow-band imaging data with MOIRCS on the Subaru telescope. We are able to construct a sample, in combination with additional H-band data taken with WFC3 on Hubble Space Telescope (HST), of 100 HAEs reaching the dust-corrected SFRs down to 3 Msun/yr and the stellar masses down to $10^{8.0}$ Msun. We find that while the star-forming galaxies with >$10^{9.3}$ Msun are located on the universal SFR-mass main sequence irrespective of the environment, less massive star-forming galaxies with <$10^{9.3}$ Msun show a significant upward scatter from the main sequence in this proto-cluster. This suggests that some less massive galaxies are in a starburst phase, although we do not know yet if this is due to environmental effects.Comment: 5 pages, 3 figures, 1 table, accepted for publication in the ApJ Letter

Clinical Usefulness of Real-time Sensory Compensation Feedback Training on Sensorimotor Dysfunction After Stroke

The sensory dysfunction after the stroke also greatly affects motor function. In particular, it is known that the presence of sensory dysfunction in the fingers causes loss of somatosensory muscle reflex control and excessive muscle output when grasping objects. These are called sensorimotor dysfunction and have been shown to have a significant impact on prognosis. One element to improve this dysfunction is to reconstruct the “Sense of Agency (SOA) subject feeling” and it has become clear that SOA is enhanced by matching the collation information related to motor intention and sensory feedback in time. In order to reconstruct the SOA associated with the movement of the fingers of patients with sensorimotor dysfunction, it is important to match motor intentions while using visual information as compensation for tactile sensory information. Furthermore, considering the functional characteristics of the fingers, it is also important to adjust the fine muscle output from feedback information synchronously discriminating and recognizing somatosensory information generated by resistance, friction, etc., when an object is actively touched. This chapter outlines the importance of rehabilitation of sensory feedback for poststroke sensorimotor dysfunction and investigates the usefulness of intervention with a real-time sensory compensation feedback system that can input tactile sensory information via vibratory stimulation (deep sensation) to other body parts where sensory function is preserved