A health status index model using a fuzzy approach

In order to derive an operational health status index, it is necessary to develop the concept of health status. An individual belongs to one of several alternative health statuses, but it is difficult to clearly identify which, because the boundaries of statuses are not sharply defined. In this paper a fuzzy approach is proposed for use in expressing the health status and its index. We deal with health status as an intrinsically ambiguous and multi-dimensional expression which is determined through some subjective judgement. We introduce the concept of fuzziness and fuzzy set in order to study the ambiguous health status. Some concepts and properties of group fuzzy measures are clarified so that we may obtain the common measure to express the health statuses. Two examples using the researched data are presented for explaining the concept of health status, the group fuzzy measures and the health status index model.     

The graphs of Lipschitz functions and minimal surfaces on Carnot groups

We study and solve a new problem for the class of Lipschitz mappings (with respect to sub-Riemannian metrics) on Carnot groups. We introduce the new concept of graph for the functions on a Carnot group, and then the new concept of sub-Riemannian differentiability generalizing hc-differentiability. We prove that the mapping-??graphs?? are almost everywhere differentiable in the new sense. For these mappings we define a concept of intrinsic measure and obtain an area formula for calculating this measure. By way of application, we find necessary and sufficient conditions on the class of surface-??graphs?? under which they are minimal surfaces (with respect to the intrinsic measure of a surface).     

Effect of self-constructed concept map with peer feedback on chemistry learning outcome

Concept mapping remains widely used in education. However, little is known about how self-constructed concept maps and peer feedback can improve student learning outcomes in chemistry. We investigated the effects of peer feedback on concept mapping and how it improves students' learning performance in a large second-semester, introductory chemistry course. Three hundred and twenty students were randomly assigned to one of two concept mapping conditions: self-constructed concept map with peer feedback and self-constructed concept map without peer feedback. Each group constructed concept maps that depicted the relationship between concepts on the topic of intermolecular force. The results showed that students in the self-constructed concept map with peer feedback condition outperformed students in the no peer feedback condition in chemistry learning outcome. Overall, this study demonstrates that peer feedback enhances the effectiveness of learning with generative concept maps. The implications and future directions are discussed.     

Involutory decomposition of a group and twisted subsets with few involutions

A subset K of some group C is called twisted if 1 ∈ K and x, y ∈ K implies that xy ^?1 x belongs to K. We use the concept of twisted subset to investigate and generalize the concept of involutory decomposition of a group. A group is said to admit involutory decomposition if it contains some involution such that the group is the product of the centralizer of the involution and the set of elements inverted by the involution. We study the twisted subsets with at most one involution. We prove that if a twisted subset has no involutions at all then it generates a subgroup of odd order.     

On S~i-quasinormal Subgroups

The objective of this paper is to invertigate the influence of maximal subgroups on the structure of a finite group.We introduce a concept of "normality" based on the permuting of certain subgroups.This concept leads to a generalization of Asaad and Shaalan's result.     

Linked systems of symmetric group divisible designs

We introduce the concept of linked systems of symmetric group divisible designs. The connection with association schemes is established, and as a consequence we obtain an upper bound on the number of symmetric group divisible designs which are linked. Several examples of linked systems of symmetric group divisible designs are provided.     

General Constructions for Double Group Divisible Designs and Double Frames

We generalize the concept of an incomplete double group divisible design and describe some recursive constructions for such a generalized new design. As a consequence, we obtain a general recursive construction for group divisible designs, which unifies many important recursive constructions for various types of combinatorial designs. We also introduce the concept of a double frame. After providing a preliminary result on the number of partial resolution classes, we describe a general construction for double frames. This construction method can unify many known recursive constructions for frames.     

DECIMAL EXTENSIONS OF THE ADDITIVE GROUP OF INTEGERS

We introduce the concept of decimal extension of the additive group of integers. We characterize these extensions as the linearly ordered abelian groups containing at least one Archimedean element. Finally, we study the additive group of rationals and its subgroups as particular cases of decimal extension.     

On sharply vertex transitive 2-factorizations of the complete graph

We introduce the concept of a 2-starter in a group G of odd order. We prove that any 2-factorization of the complete graph admitting G as a sharply vertex transitive automorphism group is equivalent to a suitable 2-starter in G. Some classes of 2-starters are studied, with special attention given to those leading to solutions of some Oberwolfach or Hamilton-Waterloo problems.     

Integration by parts for heat measures over loop groups

The formula of integration by parts for heat measures over a loop group established by B. Driver is revesited through an alternative approach to this result. We shall first establish directly the integration by parts formula over an unimodular Lie group (which will be the finite product of a compact Lie group with a correlated metric), using the concept of tangent processes. A new expression for Ricci tensor will enable us the passage to the limit.     

Linear groups as right multiplication groups of quasifields

For quasifields, the concept of parastrophy is slightly weaker than isotopy. Parastrophic quasifields yield isomorphic translation planes but not conversely. We investigate the right multiplication groups of finite quasifields. We classify all quasifields having an exceptional finite transitive linear group as right multiplication group. The classification is up to parastrophy, which turns out to be the same as up to the isomorphism of the corresponding translation planes.     

Labelings of Lee and Hamming spaces

The labeling of the Hamming Space by the rotation group and its coordinate-wise extension to give rise to the concept of -linearity. Attempts to extend this concept have been done in different ways. We deal with a natural extension question: Is there any pattern of a cyclic group G labeling of with the Hamming or Lee metric? The answer is no. Actually, we show here that Lee spaces do not allow even labelings by abelian groups, what lead us to construct labelings by semi-direct products of abelian groups. Labelings of general Hamming spaces and of Reed–Muller codes RM(1,m) are characterized here in the context of isometry groups.     

A local instructional theory for the guided reinvention of the quotient group concept

In this paper we describe a local instructional theory for supporting the guided reinvention of the quotient group concept. This local instructional theory takes the form of a sequence of key steps in the process of reinventing the quotient group concept. We describe these steps and frame them in terms of the theory of Realistic Mathematics Education. Each step of the local instructional theory is illustrated using example instructional tasks and either samples of students’ written work or excerpts of discussions.     

Second-order preferences in group decision making

We propose an aggregation method based on the concept of second-order preferences, which is capable of assigning a value function on the finite set of alternatives for each group member. This study incorporates a criterion of equity among individuals, in which everybody influences the group ranking to the same degree.     

Near integral domains on nonabelian groups

In this paper the concept of a special automorphism is introduced and used to analyze near integral domains having nonabelian addtive groups. We show that there are finite and infinite near integral domains having additive groups with arbitrary class of nilpotency. We also give another example of a non-nilpotent group which is the additive group of a near integral domain. Finally, nonabelian groups of order less than 1000 are examined to determine which can be the additive group of a near integral domain.Most of the results of this paper are contained in the author's doctoral dissertation at Boston University. The author thanks ProfessorD. W. Blackett for his guidance.     

准-1幂零群

首先给出了准-A幂零群的一个刻画,然后讨论了它与幂零群的关系,最后探讨了准-1幂零群的重要性质.     

有限群的Fuzzy次正规子群与Fuzzy极大子群

本文研究了有限群的Ｆ次正规子群，得出了一个Ｆ子群是Ｆ次正规子群的充要条件，讨论了Ｆ次正规子群的一些重要性质。另外，本文还引入了有限群的Ｆ极大子群的概念，给出了Ｆ子群是Ｆ极大群的充要条件。最后，给出了三个定理，讨论了有限群Ｇ可解、超可解、幂零与Ｇ的Ｆ次正规子群、Ｆ极大子群之间的联系。     

右$c$-群逆及其应用

研究了由右$c$-正则元确定的一类新的群逆,将之称为右$c$-群逆.证明了每个右$c$-群可逆元都是群可逆的,并通过反例说明了群可逆元未必是右$c$-群可逆的.给出了右$c$-群可逆元是群可逆元的条件,并对右$c$-群可逆元的强clean分解进行了研究.作为应用,从右$c$-群逆的角度对abelian环和直接有限环给出了一些新刻画.     

关于可解群的若干充分条件

本文在［１］的基础上，利用半正规子群的概念考查了有限群的可解性，得到了若干充分条件．     

Representation dimension of exterior algebras

We determine the representation dimension of exterior algebras. This provides the first known examples of representation dimension > 3. We deduce that the Loewy length of the group algebra over F₂ of a finite group is strictly bounded below by the 2-rank of the group (a conjecture of Benson). A key tool is the use of the concept of dimension of a triangulated category.