Editor's Notes

This issue is the first in the second 4-year term of the SIGMOD officers.
Won Kim elaborates in his Chair's Message on the new activities
of SIGMOD. I want to take this opportunity to thank the Associate Editors
who completed their term -- Hank Korth and Timos Sellis, and welcome 
Jose' Blakeley the new Associate Editor for the Database Research Surveys
section. Amit Sheth will continue to be in charge of the Section on
Database Research Centers, and Marianne Winslett will be responsible
for the the the Database Research Funding News and the Online Services.
Please read Marianne's article "SIGMOD Goes On Line" following the Chair's
Message. Portions of the SIGMOD RECORD will still be available for
anonymous FTP from segev.lbl.gov in the directory pub/SIGMOD_RECORD
(read the file README for more information). Also, I encourage
electronic submissions rather than hard-copies; please read the
inside page of the front cover for details.

Following Marianne's article, the correspondence section contains an
appeal by I. Athanasiu for helping computer scientists in Romania. 
The regular articles section contains five papers. 
The first paper "On Temporal Modeling in the Context of Object Databases",
by N. Pissinou, K. Makki,  and Y. Yesha, examines some important research
achievements in temporal databases in the past two decades and
discusses the time dimension in the context of object databases.
In the second paper, "Schema Evolution in OODBs Using Class Versioning",
S. Monk and I. Sommerville describe work carried out on a model for
the versioning of class definitions in an object-oriented database.
In "Merging Application-centric and Data-centric Approaches to 
Support Transaction-oriented Multi-system Workflows", Y. Breibart, A.
Deacon, H.-J. Schek, A. Sheth and G. Weikum argue that many applications
will be served better if the properties of transactions and workflow
models are supported by an integrated architecture. Preliminary ideas
towards such an architecture are also presented.  The fourth article,
"Database Compression" by M. A. Roth and S. J. Van Horn addresses
several aspects of reversible data compression and compression
techniques. Future research needs are also discussed.  In "Deadlock
Prevention in a Distributed Database System" P. K. Reddy and S. Bhalla
describe an algorithm for deadlock prevention which executes a
transaction by forming wait for relations with other conflicting
transactions. The authors describe this technique as free from deadlocks.

Following the section on regular articles, the reports section contains
two reports. The first is on  Workshop on Semantic Heterogeneity and
Interoperation in Multidatabase Systems by P. Drew, R. King, D. McLeod,
M. Rusinkiewicz and A. Silberschatz. That workshop was supported by NSF,
DARAPA, and US WEST. The second report is the NSF Workshop on Visual
Information Management Systems, and is written by R. Jain.

The section on Database Research Surveys contains a survey by G. Graefe
on "Options in Physical Database Design".  Several dimensions that must
be considered in database design are described including file and index
structures, vertical partitioning, clustering, replication,
materialization versioning and archival storage.  The section on
Database Research Centers covers database research activities at
the University of Florida and the University of Queensland.

In the section on Database Funding, M. Winslett and I.S. Chu discuss
"Timely Access to Future Funding Announcements". The issue is concluded
with announcements and call-for-papers. 



Arie Segev
Berkeley, California
July 1993