This paper presents the hazard analysis of the events which caused passengers to fall to the ground due to an unscheduled opening of a train door while the train is moving in Busan-Gimhase Light Rapid Train. The train has the Door/Lock function and Safety Detection of the Door Close/Lock Status as safety functions to achieve safety in order to reduce the probability of that hazard. This paper discusses the assessment to achieve safety on an unscheduled opening by the inspection given in IEC 61058 of both the safety functions. The door system was provided for BGLRT by Vapor Europe srl and the assessment based on its Technical Report[6] and SIL Analysis[7] in IEC 61068 has been carried out. According to the assessment, it is concluded that the door system is designed to minimize the probability of an unscheduled opening of door while a train is moving and that residual risk of the system is acceptable.

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Interpolational path of an operator mean has importance in the geometric sense. Here we give an equivalent condition that a symmetric operator mean in the sense of Kubo-Ando forms an interpolational path. Also we discuss some properties for interpolational means including those of another type of operator means. In addition, integral means induced by interpolational ones are introduced.

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In this paper, we give an example of a uniformly discrete metric space whose Wijsman hyperspace is not zero-dimensional, which answers a question posed by Cao, Junnila and Moors [3] negatively.

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In this article, we introduce the notion of n-fold commutative BCI-algebra, a generalization of commutative BCI-algebras. Furthermore, we generalize commutative BCI-ideals to n-fold commutative BCI-ideals and prove the extension property for n-fold commutative ideals. Finally, we use the extension property to obtain a characterization of n-fold commutative BCI-algebras in terms of n-fold commutative BCI-ideals. This work is the second part of the folding theory of BCI-algebras, the first par wast on positive implicativeness.

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Some concepts of operations on a subspace-topology are presented on a subspace of a given topological space (Definitions 2.1, 2.3) and some operation-open sets on the subspace are introduced (Definition 3.2). And we investigate some relationships among families of such operation-open sets (Theorem 3.9, Corollary 3.11). As an application, we have an operation-closure formula for a subspace (cf. Theorem 4.5).

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In the author’s recent paper [11], it is established that in a multiclass single-server queue with regular service disciplines, the stationary distributions and their moments for workload as well as for queue length can be approximated by appropriate exponential distributions and their moments in the heavy-traffic regime. In this work, relaxing the assumption of moment generating function on the primitives in that paper to the moment condition of second-order or higher-order, we obtain the corresponding approximation result in a multiclass single-server queue. The key to our analysis is to use the framework of Budhiraja and Lee [4] in which under such weak moment assumption, the tightness of stationary scaled queue length for singleclass (i.e., generalized Jackson) queueing networks is established for their stationary heavy-traffic analysis. For a multiclass single-server queue, we obtain the tightness of stationary scaled workload to show that state-space collapse occurs in the heavy-traffic regime in stationarity, from which the desired approximation result follows.

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This paper presents a stochastic differential equation model for describing the process of fish schooling. The model equation always possesses a unique local solution, but global existence can be shown only in some particular cases. Some numerical examples show that the global existence may fail in general.

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In the statistical estimation theory, sufficient conditions for admissibility of estimators have been discussed mostly under quadratic loss function. Recently, under the LINEX loss function, sufficient conditions were developed in some families of distributions. However, they do not include some typical non-regular distributions so that the dimension of the minimal sufficient statistic is two. The purpose of this paper is to give sufficient conditions for admissibility of estimators in such non-regular distributions under the LINEX loss function. Some examples are also given.

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