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UNIVERSITY OF TAMPERE
DEPARTMENT OF COMPUTER SCIENCE
P.O. Box  607
SF-33101  Tampere, Finland      


Listed below are some of the latest technical reports of our department.
Single copies are available free of charge. Quantities are limited and
orders will be filled as long as reports are available.

A-1992-3 Kalervo Jarvelin and Timo Niemi, General value conversion and 
aggregation operations: definition and integration with relational, 
entity-based and deductive data retrieval techniques. July 1992.

Abstract. Existing DBMS's do not support sufficiently advanced information 
retrieval in heterogeneous fact database environments. From the user 
viewpoint this means that many information needs cannot be satisfied 
solely by traditional fact database operations. Transitive computation, 
multi-level aggregation and value conversion are frequently needed 
together with traditional operations. The possibilities for providing 
these capabilities in fact database management systems based on the 
relational data model are considered in this paper.
  It is important that the extensions for advanced data retrieval are made 
in a uniform way with other relational processing. This means that, on 
one hand, new relational operations are developed, and on the other hand, 
non-relational operations are integrated with relational processing via 
predicates expressed within relational operations. In this paper, 
relational algebra is extended by two generalized relational operations: 
one for multi-level aggregation and the other for value conversion. 
A set of non-relational operations (called deductive operations) for 
performing transitive computation is also introduced. User's query 
formulation can also be facilitated by providing him with an entity-based 
data retrieval operation on a high abstraction level. Such a high-level 
entity-based data retrieval operation is also introduced.
  The value conversion operation provides unit of measurement-related 
transparency. It supports very versatile conversion (including conversion 
of compound attributes) and checks automatically the derivability of 
conversion requests. The conversion expressions require minimal information 
from the user. The aggregation operation provides aggregation level 
transparency. It supports, among others, multiple layered aggregation 
levels and hierarchical reclassification of the classification attributes 
determining the aggregation levels. In the data aggregation operation, 
the functional dependencies between the source and result relations 
are connected in a complex way. Both operations are defined in this 
paper in an exact way so that they construct both the instances and 
the schemas, including functional dependencies, of the result relations. 
  Complex data retrieval requires that value conversion, aggreerations 
and entity-based data retrieval operation are integrated with traditiontional 
operations. In this paper, a query language for advanced information retrieval
consisting of these operations is developed. This language allows the 
intermixing of these operations with each other without limiting the 
nesting levels. Special attention is paid to the structures, primitives 
and principles in terms of which the operations and the query language 
can be implemented. All these aspects are defined formally, in a functional 
way. In other words, the definition is independent of any programming 
language. In addition, the concretization of these aspects in a prototype 
system based on Prolog-language and a workstation environment are considered.

A-1992-2 Pertti Jarvinen, On purchasing process of a software package -
         how to teach it? April 1992.
Abstract. In the software industry there is a mass production of packages 
for some well-defined purposes, as for text processing, network management, 
book-keeping, budgeting etc. Different suppliers produce packages intended 
for the similar tasks, and they have both the same and slightly differing 
features. The proportional importance of software costs compared with hardware
costs is still increasing.  Hence, selection of the package is a problem 
proper where particular knowledge and skills are needed.  
  The course on "purchasing of a software package" was organized by 
this author in two last springs in the University of Tampere. The course 
was intended to students in computer science, but one third of the 
participants were from other disciplines, called application sciences. This 
fact gave an opportunity to form groups with three students, two from 
computer science and one from application sciences. The latter person 
played an important role, when a group defined its needs and requirements. 
Each group had chance to define its purchasing order, i.e. a software 
package to be purchased. Some of the orders were real ones and some others 
tentative ones.
  The local software companies allowed the groups to visit and to 
negotiate whether the package offered was suitable to the purposes defined 
by the group. After collecting the data about candidate packages the student 
groups made a comparison and then recommended one of the packages to be 
purchased. The groups also considered the ready made contracts and planned 
their proposals for changes and amendments to the conventional contracts.
  In this paper I shall describe the pros and cons of the approach 
outlined above. I will also give short descriptions of the reports prepared 
by the groups, actions to be taken and evaluation of various features of 
the course. The students expressed their views on teaching and working 
modes, on assessment of learning and on the whole approch. Students' 
evaluation was rather positive. This strongly supports the approach 
selected. The recommendations for improving our approach are minor and 
concern such wishes as changing starting time (8 o'clock) and usage of 
teaching material.

A-1992-1 Pertti Jarvinen, Impacts of electronic markets on work. 
         January 1992.
Abstract. The domain of electronic markets are increasing in relation 
to electronic hierarchies. Hence it is important to analyze possible 
impacts of electronic markets on a human being at work. A man can be in
different positions concerning electronic markets: 1. a developer of an 
inter-organizational information system (IOS), 2. a user (a seller or a 
buyer) of electronic markets,  and 3. an object of markets, i.e. a
specialist whose services are sold on electronic markets.
  First, to construct the IOS a developer has to perform particular
tasks: requirements analysis, design, implementation and thereafter 
often also maintenance. Second, a user of electronic markets can do 
different things  depending on whether she/he is working in a producer 
company, in a distributor firm, in a buyer company, in a network provider 
company or in financial services. Third,  services offered by a human 
being  on electronic markets should inform potential buyers about her 
or his service. On the other hand a buyer must describe which kind of 
service she or he needs.firm, in a buyer company, in a network provider 
company or in financial services potential buyers about her or his service. 
On the other hand a buyer must describe which kind of service she or he 
needs.
  In the first position, the idea of the IOS means that the production/
consumption chain is lengthened. The developer of the IOS must master this 
chain over two or more organizations. Hence, she or he must be more competent 
than nowadays. Concerning the second position, a user of electronic markets, 
by definition, will lose social contacts. Her variety to communicate will 
diminish, because she or he must use the standardized product/service 
description language and/or the information retrieval language at hand. In 
the third position, the services offered by a certain expert must be described 
as in detail as possible. But this creates a dilemma, if a task can be 
described in elementary operations, it could be automated, i.e. the task 
is no more necessarily performed by  a human being but by a computer or by 
an automaton.

A-1991-9 Pentti Hietala and Jyrki Nummenmaa, MEDUSA - A multimodal database 
         user interface with a computer supported learning aid. December
         1991.
Abstract. In this paper we introduce an approach and a corresponding 
system combining facilities for natural language processing,
graphical query formulation, and knowledge-based user assistance
under a unified user interface. We discuss also our plans to
iteratively evaluate and improve the system through field evaluation
and data collected by the knowledge-based user assistant. Moreover, 
our framework provides a fruitful environment for a more general 
comparison and evaluation of different user interaction modalities to 
be performed during the iterative evaluation process.

A-1991-4 Esa Helttula, Manipulating disjoint sets: algorithms, testing,
         and animation, June 1991.
Abstract. An analysis and an animation program of algorithms for the union-
find problem is presented. The analysis program can be used to graphically 
compare the running times of different algorithms by counting the number 
of basic operations and assigning costs for them. It can also be used to 
study how the data structures of those algorithms change during execution. 
All classic algorithms and some new variations are tested empirically. The 
variations and some not optimal algorithms are found to outperform the 
classic algorithms in some cases. The animation program gives the user the 
possibility to try out different classic union-find algorithms and union-
find-deunion algorithms.

A-1991-3 Pertti Jarvinen, On approaches in information systems research,
         June 1991.
Abstract. The domain of information systems (IS) research is very wide. 
The components of an IS and the main stages in the IS life cycle are 
different by nature.
There are deterministically behaving hardware and software components.
The same cannot be said about users, i.e. about conscious human beings
having free will. The use and the maintenance of the information system
are not the only stages or processes concerned, but we are also interested
in how to design and implement a new information system. This means that
in addition to discovering a current reality we are also studying how to
construct a new reality. The one and same research approch is not valid
for doing research work concerning different components and processes.
In the recent research of central topics as: causality, determinism, dynamical
systems and theories of acts,  some fundamental similarities and
differences are found. In various taxonomies of IS research there are
different classifications of the legitimated approaches. A reader may
have difficulties to understand whether the difference between two
particular approaches is great or slight, and whether a certain approach
is applicable to a particular purpose. Based on those fundamental
similarities and differences of the central topics our aim is to show a) which
research approaches are in a certain sense "relatives" and which are not,
and b) which research approach is suitable for a particular purpose.
Approaches are broad-mindedly classified to four "families": Firstly, causal
models, statistics, field test and laboratory experiment seem to belong to
the category of theorem-proving causal approaches; secondly, case study,
action research, hermeneutics and phenomenology respectively to the category
of sensitive exploratory approaches catching a current reality. Thirdly,
we identify mathematical approaches containing e.g. formal methods and
cybernetics. Fourthly, there are also constructive approaches suitable
for studying how to construct a new reality. Hopefully these families or
groupings of research approaches might increase the awareness of
the applicability of a particular approach. This is very important in
the IS society emphasizing methodological pluralism. (Presented at the 
IRIS'14 in Umea (Sweden), August 12-14,1991.)

A-1990-7 Erkki Makinen, Remarks on the assignment heuristic for drawing
bipartite graphs. August 1990. 

A-1988-10 Hannu Kangassalo, COMIC -  A system for conceptual modelling and 
information construction, December 1988.

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