（Dis）Economies of Scale in Business Software Systems Development and Enhancement Projects

In the software engineering literature, it is commonly believed that economies of scale do not occur in case of software Development and Enhancement Projects （D＆EP）. Their per-unit cost does not decrease but increase with the growth of such projects product size. Thus this is diseconomies of scale that occur in them. The significance of this phenomenon results from the fact that it is commonly considered to be one of the fundamental objective causes of their low effectiveness. This is of particular significance with regard to Business Software Systems （BSS） D＆EP characterized by exceptionally low effectiveness comparing to other software D＆EP. Thus the paper aims at answering the following two questions： （1） Do economies of scale really not occur in BSS D＆EP？ （2） If economies of scale may occur in BSS D＆EP, what factors are then promoting them？ These issues classify into economics problems of software engineering research and practice.

Semantic Differential as an Assessment Tool of （Dis） Advantages of QMS in the Light of Accredited Certification in Poland

This article is a continuation of the issue in the field of assessment of （dis）advantages resulting from the implementation of the quality management systems （QMS） in a structure of the organization. The publication uses the results of studies conducted in the range of assessment＇s information completeness provided by the certification bodies （CBs） in the context of advantages and disadvantages of the QMS implementation in accordance with PN-EN ISO 9001. In addition, an attempt to define a tool for the QMS assessment of （dis）advantages in the organization has been made. The basis for empirical analysis of the issue was the information provided by an accredited management systems CBs recommended by the Polish Centre for Accreditation （PCA）. There are 33 units in Poland, which were granted by PCA with the accreditation within the range of ISO 9001：2008. In the first stage of the research work, a substantive analysis of websites content among mentioned CBs has been carried out. In addition, the paper proposes use of semantic differential method （SD） to evaluate （dis）advantages of the QMS. SD adaptation for the assessment of the QMS （dis）advantages is the authorial concept. The authors hope for polemic in this area. In the face of obtained results, an authorial SD construction has been proposed, which is useful and may help in the formulation and conveying of the relevant （reliable） information to potential clients in the range of （dis）advantages resulting from the QMS implementation to the organization. As a consequence, the recommendations have been set, which are kind of guidelines that could significantly influence the realignment of the information state conveyed on the internet by the CBs.

Modeling and simulation of torpedo acoustic homing trajectory with multiple targets

The characteristics of a torpedo＇s acoustic homing trajectory with multiple targets were studied. The differential equations of torpedo motion were presented based on hydrodynamics. The Fourth order Runge-Kutta method was used to solve these equations. Derived from sonar equations and Snell＇ s law, a simple virtual underwater acoustic environment was established for simulating the torpedo homing process. The Newton iteration method was used to calculate homing range and ray tracing was approximated by pieccwise line, which takes into consideration distortions cause by temperature, pressure, and salinity in a given sea area. The influence of some acoustic warfare equipment disturb the torpedo homing process in certain circumstances, including decoys and jammers, was alsotaken into account in simulations. Relative target identification logic and homing control laws were presented. Equal consideration during research was given to the requirements of rcal-timeactivity as well as accuracy. Finally, a practical torpedo homing trajectory simulation program was developed and applied to certain projects.

A simple experimental scheme for M-QAM optical signals generation

A simple scheme to generate optical quad- rature amplitude modulation （QAM） signals is proposed based on different types of delay interferometers （Dis）. The simulated results show that 16QAM, 64QAM and 256 QAM optical signals can be generated by 2×2, 3 ×3 and 4×4 DI, respectively, and the outputs of the proposed scheme are similar to those of the conventional schemes. The operation principle is discussed and the transmission properties of the square 16QAM as well as 64QAM signals are analyzed and compared with common approach.