Loss of postural stability can increase the likelihood of slips and falls in workplaces. The present study intended to extend understanding of the effects of frequency and pressure level of sound on postural stability during standing. Eleven male subjects participated. Standing on a force platform, the subjects' center of pressures were measured under different combinations of pressure level and frequency of the sound. Variables such as the position variability of COP and the length of postural sway path in anterior-posterior (AP) and medio-lateral (ML) direction were evaluated. Subjective ratings of perceived disturbance at each experimental condition were also obtained using a 7-point rating scale. Results showed that the length of sway path and the position variability of COP increased as the frequency of sound increased in posterior-anterior axis. The effect of sound pressure level, however, was not significant on both the postural sway length and the position variability of COP. These results suggested substantial disturbance of standing balance system among subjects exposed to high frequency noise. The results implied that physical workers should be alerted that their abilities of postural balance could be degraded significantly as disturbance caused by a sound existed.

A laboratory study was conducted to evaluate if age-related gait adaptations in walking velocity, step length and heel contact velocity could adversely influence friction demand characteristics (i.e. RCOF) and the likelihood of slip initiation. Additionally, relationship between transitional acceleration of the whole body center-of-mass (COM) and friction demand was assessed between young and older participants. Fourteen younger (7 females and 7 males, 18-30 years old) and 14 older (7 females and 7 males, over 65 years old) adults participated in the study. While wearing a safety harness, all participants walked at their preferred gait speed for approximately 20 min on the linear walking track, and synchronized ground reaction forces and posture data were captured using the force plates and six infrared cameras, respectively.The results indicated that older adults walked slower with slower heel contact velocity, and produced lower friction demand (i.e. RCOF) in comparison to younger adults. However, ANCOVA indicated that the differences in heel contact velocity between the two age groups were due to effects of walking velocity. The multiple regression and bivariate regression analyses suggested that, for older adults, heel contact velocity was a predictor for the RCOF, whereas, for younger adults, walking velocity, step length and transitional acceleration of the whole body COM were the factors contributing to the RCOF.In conclusion, the present study suggested that gait adaptations among the elderly must be considered when predicting the likelihood of slip initiation.

We report highly efficient organic photosensitizers containing pi-conjugated alkoxy-substituted oligophenylenevinylene linkers with electron donor-acceptor units for dye-sensitized solar cells. TA-DM-CA showed an overall solar-to-energy conversion efficiency of 9.67% at AM 1.5 illumination (100 mW cm(-2)).

Abstract-We describe a new tiling approach for network code number of transmissions required. The savings is achieved design. The proposed method applies dynamic programming to because in this case node v2 can pass along both messages in a find the best strategy among a restricted collection of network single coded transmission. Precisely nodes v, and V3 transmit codes. We demonstrate the proposed strategy as a method for sgcoed transmissio n.Pecisely, nodes v efficiently accommodating multiple unicasts in a wireless coding pakes t ae to bnod vf(tw twransisi) ndet environment on a triangular lattice and discuss its generalization. V2 takes the bit-wise binary sum of its two received packets (X1,3 e X3,1) and then broadcasts the sum (one transmission).Since both nodes v1 and V3 are within transmission range of I. INTRODUCTION node V2, both receive the mixture packet (X1,3 e X3,1). Node We consider the problem of information flowfin wire-v1 decodes X3,1 by taking the binary sum of X1,3 e X3,1 and less mesh networks. Each coding network in the family of its known value of X313. Node V3 similarly knows X3,1 and problems considered contains wireless nodes arranged on the receives X1,3 e X3,1, from which it can decode X1,3 vertices of a triangular lattice (see Figure 1). The networkThe given strategy generalizes from single packet transmisis completely wireless, so each node can communicate only sions across a two-hop network to information flows across a through transmission and receipt of wireless broadcasts. A path with arbitrarily many hops. We call this strategy reverse given wireless node can broadcast information only to nodes carpooling. We use the word "carpooling" because the method in its six neighboring locations. Similarly, a given wireless allows two messages to effectively share a ride through the node directly receives all transmissions sent by its immediate network: After an initial set-up period, every time an internal neighbors and no transmissions sent by nodes at a greater node transmits, it transmits a bit-wise binary sum of the next distance. packet that it intends to send forward and the next packet that it intends to send backward along the path. For long paths and long sequences of packets the savings approaches a factor of two. We call it "reverse" carpooling because the strategy only applies when the information flows that want to share a ride are traveling opposite directions. In addition to the reverse carpooling advantage, network coding is useful at network cross roads, as illustrated in Figure 2(b). Here a single packet (X1,4) passes from node V1 to node V4, another (X3,6) from node V3 to node v6, and a third (X5,2) from node V5 to node v2, The routing solution requires a minimum of six transmissions as each Fig. 1. The nodes of our network lie on the vertices of a triangular lattice. node transmits its known packet to node V7, which then sends each message along separately. In the network coding solution, Even for transmission of independent messages, network here called star codin...

Abstract-We study network error correction with unequal link capacities. Previous results on network error correction assume unit link capacities. We consider network error correction codes that can correct arbitrary errors occurring on up to z links. We find the capacity of a network consisting of parallel links, and a generalized Singleton outer bound for any arbitrary network. We show by example that linear coding is insufficient for achieving capacity in general. In our example, the capacity is 50% greater than the linear coding capacity and we achieve using a nonlinear error detection strategy. We also present a method for finding an upper bound on the linear coding capacity for arbitrary network. We show that even for a single source and single sink network, it may be necessary for intermediate nodes to do coding, nonlinear error detection or error correction. This is unlike the equal link capacity case, where coding only at the source and forwarding at intermediate nodes suffices for a single source and sink network. We conjecture that the generalized Singleton outer bound is not achievable in general.