Influences of the edge radius of curvature of tactile dots and bars on their Discriminability

Tactile dots and bars serve as tactile landmarks so that people with visual impairment can use same consumer products as those used by sighted people. However, reliable age-related data on the appropriate sizes and the shapes was not necessarily available. The purpose of this study is to evaluate influences of edge radius of curvature of tactile dots and bars on their discriminability in younger and older people to determine the appropriate size of tactile bars (as distinguished from tactile dots). Sighted younger and older participants tactually discriminated the tactile dots and bars presented individually, in random order, by a two-alternative forced-choice task. The results showed that both participants discriminated tactile bars from tactile dots faster and more accurately as the dimensional difference between bar length and width increased, regardless of conditions of edge radius of curvature. Therefore, longer dimensional difference between width and length of tactile bars is an important factor to discriminate tactile bars correctly. On the other hand, tactile dots with a larger edge radius of curvature have higher discriminability than tactile dots with a smaller edge radius of curvature in the case of dots of identical height.     

Average-case competitive analyses for one-way trading

Consider a trader who exchanges one dollar into yen and assume that the exchange rate fluctuates within the interval [m,M]. The game ends without advance notice, then the trader is forced to exchange all the remaining dollars at the minimum rate m. El-Yaniv et al. presented the optimal worst-case threat-based strategy for this game (El-Yaniv et al. 2001). In this paper, under the assumption that the distribution of the maximum exchange rate is known, we provide average-case analyses using all the reasonable optimization measures and derive different optimal strategies for each of them. Remarkable differences in behavior are as follows: Unlike other strategies, the average-case threat-based strategy that minimizes E[OPT/ALG] exchanges little by little. The maximization of E[ALG/OPT] and the minimization of E[OPT]/E[ALG] lead to similar strategies in that both exchange all at once. However, their timing is different. We also prove minimax theorems with respect to each objective function.     

Approximating capacitated tree-routings in networks

Let G=(V,E) be a connected graph such that each edge e∈E is weighted by a nonnegative real w(e). Let s be a vertex designated as a sink, M?V be a set of terminals with a demand function q:M→R ⁺, κ>0 be a routing capacity, and λ≥1 be an integer edge capacity. The capacitated tree-routing problem (CTR) asks to find a partition ?={Z ₁,Z ₂,…,Z _? } of M and a set \({\mathcal{T}}=\{T_{1},T_{2},\ldots,T_{\ell}\}\) of trees of G such that each T _i contains Z _i ∪{s} and satisfies \(\sum_{v\in Z_{i}}q(v)\leq \kappa\). A single copy of an edge e∈E can be shared by at most λ trees in \({\mathcal{T}}\); any integer number of copies of e are allowed to be installed, where the cost of installing a copy of e is w(e). The objective is to find a solution \(({\mathcal{M}},{\mathcal{T}})\) that minimizes the total installing cost. In this paper, we propose a (2+ρ _ST )-approximation algorithm to CTR, where ρ _ST is any approximation ratio achievable for the Steiner tree problem.     

Improved estimation for the autocovariances of a Gaussian stationary process

For a Gaussian stationary process with mean μ and autocovariance function γ(·), we consider to improve the usual sample autocovariances with respect to the mean squares error (MSE) loss. For the cases μ=0 and μ≠0, we propose sort of empirical Bayes type estimators Γ? and Γ?, respectively. Then their MSE improvements upon the usual sample autocovariances are evaluated in terms of the spectral density of the process. Concrete examples for them are provided. We observe that if the process is near to a unit root process the improvement becomes quite large. Thus, consideration for estimators of this type seems important in many fields, e.g., econometrics.     

Training the nation’s elites: National–private sector differences in Japanese university education

I examine the relationship between university prestige and socioeconomic achievement in Japan. I generate a set of hypotheses based on human capital and screening models of education, and test these using a 1995 cross-sectional dataset. I find that university prestige significantly improves socioeconomic achievement among male university graduates in Japan. I also find that national university graduates have higher rates of return to their university education, and are more likely to be employed in higher prestige occupations than are private university graduates. My findings lend support to the ‘elite’ view of investments in human capital proposed by Becker (1993), under which higher ability individuals (in this case national university graduates) have more to gain from university education than do lower ability individuals. I find little support for the screening model of education.     

A Note on the Max-Min 0-1 Knapsack Problem

In this paper we propose new lower and upper bounds for the max-min 0-1 knapsack problem, employing a mixture of two relaxations. In addition, in order to expose whether the bounds are practical or not, we implement a method incorporating the bounds to achieve an optimal solution of the problem.     

Marriage,Cohabitation, and Happiness: A Cross‐National Analysis of 27 Countries

The authors investigated how the reported happiness of married and cohabiting individuals varies cross‐nationally with societal gender beliefs and religious context. They used the 2002 International Social Survey Programme data from 27 countries (N = 36,889) and specified hierarchical linear models with macro – micro level interactions in order to examine how the social – institutional context affects happiness at the individual level. Consistent with previous research, they found a happiness gap between married and cohabiting persons. In the case of women, this gap was moderated by the gender climate and the religious context in the country. This suggests that, at least for women, this gap is not intractable but is rather an outcome of the social context. For men, the relationship between marital status and happiness was less variable across the different social contexts studied.