Comprehension of object-oriented software cohesion: The empirical quagmire

Chidamber and Kemerer (1991) proposed an object-oriented (OO) metric suite which included the Lack of Cohesion Of Methods (LCOM) metric. Despite considerable effort both theoretically and empirically since then, the software engineering community is still no nearer finding a generally accepted definition or measure of OO cohesion. Yet, achieving highly cohesive software is a cornerstone of software comprehension and hence, maintainability. In this paper, we suggest a number of suppositions as to why a definition has eluded (and we feel will continue to elude) us. We support these suppositions with empirical evidence from three large C++ systems and a cohesion metric based on the parameters of the class methods; we also draw from other related work. Two major conclusions emerge from the study. Firstly, any sensible cohesion metric does at least provide insight into the features of the systems being analysed. Secondly however, and less reassuringly, the deeper the investigative search for a definitive measure of cohesion, the more problematic its understanding becomes; this casts serious doubt on the use of cohesion as a meaningful feature of object-orientation and its viability as a tool for software comprehension

Object-oriented cohesion as a surrogate of software comprehension: An empirical study

The concept of software cohesion in both the procedural and object-oriented paradigm is well known and documented. What is not so well known or documented is the perception of what empirically constitutes a cohesive 'unit' by software engineers. In this paper, we describe an empirical investigation using object-oriented (OO) classes as a basis. Twenty-four subjects (drawn from IT experienced and IT inexperienced groups) were asked to rate ten classes sampled from two industrial systems in terms of their overall cohesiveness; a class environment was used to carry out the study. Four key results were observed. Firstly, class size (when expressed in terms of number of methods) did not tend to influence the perception of cohesion by any subjects. Secondly, well-commented classes were rated most highly amongst both IT experienced and inexperienced subjects. Thirdly, the empirical study suggests that cohesion comprises a combination of various class factors including low coupling, small numbers of attributes and well-commented methods, rather than any single, individual class feature per se. Finally, the research supports the view that cohesion is a subjective concept reflecting a cognitive combination of class features; as such it is a surrogate for class comprehension

Intergenerational transfers in rural households: A game theoretical approach

The household membership decision is viewed as a “research project” where the offspring invests in human and non human capital to influence the probability of finding an alternative to the parental household. The problem is formulated as a differential game between a selfish offspring and altruistic parents. The solution is consistent with facts” such as the “flexibility of inheritance systems” and the “generational fragmentation” of the family property when the economic opportunities expand outside the parental household.intergenerational transfers, rural households, game theory

Values, norms, transactions and organizations

This paper may be considered an essay on metaeconomics, since it deals with the meaning of several concepts often left undefined, or very briefly defined in economic theories. These concepts are the following: value including the values of things and moral values, social norms or institutions, social power, goods and services, transactions and organizations (firms, and others). The paper starts by proposing a general concept of value, encompassing both the value of things and moral values. From this concept it proceeds to the definition of six different types of values of things and moral values and to the concept of value transformation process of things which includes all the operations dealt with in economic theory as well as many other human actions. The last part of the paper starts with the distinction between moral values and social norms (or institutions) and the roles of social power and human organization in connecting the domains of morality and social normativity. The paper proceeds by distinguishing different types of norms, including possession norms which are important for defining the concepts of goods and services and transaction processes.

Forest owners’ collective action against the risk of forest fire: a game theoretical approach

This paper is a follow up on a earlier one (Mendes, 1998) where I proposed a series of models for forest owners associations represented as organisation made up of two groups of strategically interacting players: the forest owners who are members of the association and the board of directors they have elected. The directors decide on the amount of services provided by the association which can be public goods (collective representation of the members, promotion of their common interests, diffusion of general information about forest programmes and best forest management practices, etc.) and private goods and services (silvicultural works preventive of forest fires, technical advice, etc.). The models were set up as games in strategic form with complete information and no payoff uncertainty. Here I pick up the second of, what is called in that previous paper, the "Portuguese" models and extend it in the following directions: - there is payoff risk for the forest owners due to exogenous hazards (forest fires or others); - forest owners can buy private services from the owners which contribute to reduce the losses resulting from those hazards. The main focus in this paper is to derive the comparative static results about the demand of these private services by the forest owners.forest owners’ associations, public and private goods joint supply, game theory