Browsing by Author "CHEN, JY"

Now showing 1 - 14 of 14

A NEW METRIC FOR OBJECT-ORIENTED DESIGN
(1993-04-01)
CHEN, JY
;
LU, JF
;
交大名義發表
;
資訊工程學系
;
National Chiao Tung University
The paper presents a new metric for the object-oriented design. The metric measures the complexity of a class in an object-oriented design. The metrics include operation complexity, operation argument complexity, attribute complexity, operation coupling, class coupling, cohesion, class hierarchy, and reuse. An experiment is conducted to build the metric system. The approach is to derive a regression model of the metrics based on the experimental data. Moreover, the subjective judgement by the expert is incorporated in the regression model. This ensures that the metric system is pragmatic and flexible for the software industry.
A NEW OBJECT-ORIENTED METHOD INTEGRATING JACKSON STRUCTURED PROGRAMMING METHOD
(1994-02-01)
CHEN, JY
;
CHEN, YTT
;
資訊工程學系
;
Department of Computer Science
This article presents a new object-oriented method which integrates the Jackson Structured Programming method with an object-oriented approach. The new method analyzes the user's services, identifies attributes from data structure diagrams, and identifies operations from program structure diagrams. Also, this method defers the identification of class relationships until the attributes and operations have been identified, so as to prevent premature decisions. In addition, the concept of ''leading object'' is used to decrease the number of actors and agents and to increase the number of servers in a system. This may enhance reusability of the objects.
AN ADA-LIKE SOFTWARE PROCESS LANGUAGE
(1994-10-01)
CHEN, JY
;
TU, CM
;
資訊工程學系
;
Department of Computer Science
This article presents a new software process language called concurrent software process language (CSPL). CSPL demonstrates a unique approach in combining the Ada-like syntax with UNIX shell semantics within a software process language. The rich Ada constructs allow CSPL to model the complexity in software processes. Meanwhile, the UNIX shell provides process enaction and, more importantly, easy access to powerful UNIX tools. A CSPL prototype has been built on the Sun workstation. Examples illustrate how CSPL can be used to model objects, activities, events, generics, exceptions, etc., in software processes. Moreover, a meta-process is given to depict a process of developing CSPL process programs. Related work and a preliminary evaluation of CSPL are also depicted.
AN ENACTABLE SOFTWARE PROCESS MODELING APPROACH
(1993-10-01)
CHEN, JY
;
LAI, CP
;
交大名義發表
;
資訊工程學系
;
National Chiao Tung University
Software process modelling has attracted much attention in the software engineering community in recent years. A software process model should be able to model distributed concurrent software processes. Moreover, it should be enactable. This article proposes a software process modelling approach which integrates three representations, namely, the Activity On Vertex net (AOV net), the Software Process Petri Net (SPPN), and the Concurrent Software Process Language (CSPL). First, the AOV net models take precedence and concurrency between process activities. Second, the AOV net is transformed into SPPN which models comprehensive information in the software process. Third, the SPPN is transformed into a CSPL process program which is executed in a distributed software development environment to enact a software process. Additionally, the modelling approach can analyse some undesirable states in the software process.
AN INTEGRATED OBJECT-ORIENTED ANALYSIS AND DESIGN METHOD EMPHASIZING ENTITY CLASS RELATIONSHIP AND OPERATION FINDING
(1994-01-01)
CHEN, JY
;
HUNG, YS
;
資訊工程學系
;
Department of Computer Science
This paper presents an object-oriented analysis and design (OOAD) method that integrates analysis and design phases based on entity and class relationships. This method concentrates on establishing relationships between entities and between classes and on representing and refining the relationships. In describing the system's behavior, this method provides modified event trace diagrams and a textual document to capture the interactions among operations within the classes. It also provides uniform notations and specific procedures in order to identify classes, objects, attributes, and operations.
AN OBJECT-ORIENTED METHOD FOR SOFTWARE MAINTENANCE
(1994-01-01)
CHEN, JY
;
CHANG, SCV
;
資訊工程學系
;
Department of Computer Science
CSPL - A PROCESS-CENTERED ENVIRONMENT
(1994)
CHEN, JY
;
TU, CM
;
交大名義發表
;
資訊工程學系
;
National Chiao Tung University
This paper introduces a software process language called 'Concurrent Software Process Language' (CSPL) to serve as a process-centred environment. 'Concurrent' implies that the CSPL is capable of modelling the concurrency in software processes. The CSPL syntax inherits mostly from Ada, and the CSPL semantics is in the Unix shell. A CSPL process program is translated into Unix shell to enact (execute) a software process. Examples are given to illustrate how the CSPL provides environmental supports to guide, automate or simulate software processes. A CSPL prototype is currently developed on the Sun workstation.
CUTOFF RATES OF MULTICHANNEL MFSK AND DPSK SIGNALS IN MOBILE SATELLITE-COMMUNICATIONS
(1995-02-01)
SU, YT
;
CHEN, JY
;
電信工程研究所
;
友訊交大聯合研發中心
;
Institute of Communications Engineering
This paper studies the coded performance of multichannel MFSK and DPSK signalings in mobile satellite environments characterized by various kinds of multipath fading. Rician, Rician/lognormal, and a convex combination of Rician and Rician/lognormal or Rayleigh/lognormal distributions are used to model these communication channels. We investigate the minimum average signal-energy-to-noise ratio required to yield a cutoff rate that is greater than or equal to a given code rate. Also examined are system design issues such as the effect of quantization and metric conversion, the choice between binary codes and M-ary symbol codes, the optimization of the diversity order and the signal size, and the order of deinterleaving and diversity combining. Numerical examples are given to answer concerns raised by these issues.
DEPOLYMERIZATION OF POLY(ETHYLENE-TEREPHTHALATE) RESIN UNDER PRESSURE
(1991-03-20)
CHEN, JY
;
OU, CF
;
HU, YC
;
LIN, CC
;
應用化學系
The process of depolymerization of PET resin by EG glycolysis under pressure is investigated. The kinetics of this pressurized depolymerization of PET resin is discussed. It was found that the rate of deploymerization is dependent of temperature, pressure, and concentration ratio of EG to PET. The rate of depolymerization is proportional to the square of EG concentration and faster than that under atmospheric pressure. Glycolyzed products under pressure consist of the PET monomer, BHET, and oligomers, mostly dimer and trimer. An equilibrium between BHET and oligomers is attained quickly soon after the deploymerization step is completed in the case of a higher ratio of EG/PET used. In the case of lower ratio of EG/PET, the final product now consists of molecular weight of oligomers rather than monomer, dimer, and trimer.
ELECTROLUMINESCENCE OF A-SIC-H P-I-N THIN-FILM LIGHT-EMITTING-DIODES WITH QUANTUM-WELL-INJECTION STRUCTURES
(1994-09-01)
JEN, TS
;
SHIN, NF
;
TSAY, WC
;
CHEN, JY
;
NING, SL
In order to improve the electroluminescence (EL) characteristics of hydrogenated amorphous silicon carbide (a-SiC:H) p-i-n thin-film light-emitting diodes (TFLEDs), the quantum-well-injection (QWI) structures have been incorporated into their intrinsic (i-) layer. Two types of TFLED were fabricated to study the effect of the incorporated QWI structures on their EL characteristics: the device I contains a step-gap QWI structure of barrier (15 angstrom)/well (45 angstrom)/barrier (15 angstrom) inserted at both the p-i and i-n interfaces, and the device Il has only one graded-gap QWI structure of barrier (10 angstrom)/well (10 angstrom)/barrier (10 angstrom) inserted at the p-i interface. The obtained brightness of device I was about 10 cd/m2 at an injection current density of 1 A/cm2. The emission light of device I was yellow-like as detected by human eyes. Whereas, for device II, the brightness was about 256 cd/m2 at 800 mA/cm2 and an orange light emission was observed.
HYDROGENATED AMORPHOUS SILICON-CARBIDE THIN-FILM LIGHT-EMITTING DIODE WITH QUANTUM-WELL-INJECTION STRUCTURE
(1993-04-15)
JEN, TS
;
CHEN, JY
;
SHIN, NF
;
HONG, JW
;
CHANG, CY
To improve the electroluminescence (EL) intensity of the hydrogenated amorphous silicon carbide (a-SiC:H) pin thin-film light-emitting diode (TFLED), a quantum-well-injection (QWI) structure has been incorporated into the i-layer of an a-SiC:H pin TFLED at the p-i interface. The obtained brightness of this QWI TFLED is 256 cd/m2 at an injection current density of 800 mA/cm2, which is about three orders of magnitude higher than the brightness of an a-SiC:H pin TFLED. Also, a comparatively lower EL threshold voltage of 6 V was observed for this a-SiC:H QWI TFLED.
HYDROGENATED AMORPHOUS-SILICON CARBIDE DOUBLE GRADED-GAP P-I-N THIN-FILM LIGHT-EMITTING-DIODES
(1993-09-01)
SHIN, NF
;
CHEN, JY
;
JEN, TS
;
HONG, JW
;
CHANG, CY
Hydrogenated amorphous silicon carbide (a-SiC:H) p-i-n thin-film light-emitting diodes (TFLED's) with graded p+-i and i-n+ junctions have been proposed and fabricated successfully on an indium-tin-oxide (ITO)-coated glass. An obtained orange TFLED reveals a brightness of 207 cd/m2 at an injection current density of 600 mA/cm2, which is the brightest one ever reported for a-SiC:H TFLED's at the same injection current density. This significant increase of brightness could be ascribed to the combined effect of reduced interface states by using the graded-gap junctions, lower contact resistance due to post-metallization annealing, and higher optical gaps of the doped layers.
MDL (METHODOLOGY DEFINITION LANGUAGE) - A LANGUAGE FOR DEFINING AND AUTOMATING SOFTWARE-DEVELOPMENT PROCESSES
(1992-07-01)
CHEN, JY
;
HSIA, P
;
資訊工程學系
;
Department of Computer Science
This paper discusses a Methodology Definition Language that can be used to define the software development method. Together with the support of the language processor called the environment generating system, this language can be used to define a specially tailored method for any particular software development process and generate a computer-guided environment for the method defined. The syntax of the language is defined using the BNF grammar, and the semantics of the language is defined by an executable language (a command language). A prototype system of this language has been implemented under the VAX/VMS system. Experiences using this prototype to exercise methodologies show that the approach is very versatile and may improve the quality of development process.
STUDIES ON CO[POLY(ETHYLENE TEREPHTHALATE-P-OXYBENZOATE)]THERMOTROPIC COPOLYESTER (I) - SYNTHESIS AND THERMOGRAVIMETRIC BEHAVIOR
(1993-02-15)
SHINN, TH
;
CHEN, JY
;
LIN, CC
;
應用化學系
;
Department of Applied Chemistry
A series of co[poly (ethylene terephthalate-p-oxybenzoate)] thermotropic copolyester was synthesized from various ratios of two different moieties of either poly(ethylene terephthalate) (PET) or its oligomer as moiety (II) with p-acetoxybenzoic acid as moiety (I) through the polycondensation process. The polymeric products obtained were then ground and subjected to solid-state polymerization under vacuum for various polymerization times. Thermogravimetric analysis (TGA) and the derivative thermogravimetric analysis (DTG) were performed with these samples obtained. Also, a commercial product, Eastman 10109, was analyzed in comparison with these samples. It was found that the copolyesters made of PET and of its oligomer in a p-oxybenzoate (POB):PET = 80:20 composition ratio and subjected to 8 and 4 h solid-state polymerization times, respectively, showed the most similar thermogravimetric behavior with Eastman 10109.