نتایج جستجو برای: through conceptual and logical method
تعداد نتایج: 17195351 فیلتر نتایج به سال:
ABSTRACT Conceptual level database design should be managed independently of its implementation. Therefore, once a conceptual level schema has been completed, some transformation method must exist which can be used in the construction of an implementation level design supported by the target model (e.g., relational, objectoriented, network). This paper provides a method for the transformation o...
a significant problem in multicarrier communication systems is the necessity to reduce the value of papr (peak-to-average power ratio) of transmitting signal. in this thesis we study the effect of the system parameters such as coding and modulation types on papr and ultimate ber in a mc-cdma system. in this study we consider fading channel as well as the nonlinearity of transmitter’s amplifier ...
the present study was an attempt to conduct a contrastive analysis between general english (ge) and english for specific purposes (esp) texts in terms of cohesion and cohesive devices. to this end, thirty texts from different esp and ge textbooks were randomly selected. then they were analyzed manually to find the frequency of cohesive devices. cohesive devices include reference, substitution, ...
a simple, sensitive and selective method for solvent extraction and spectrophotemetric determination of lanthanum (ii) europium (iii), and cerium (iii) is described , the rare earth metals are extracted into chloroform solution of n-phenylbenzohydroxamic acid (pbha) at ph 9-10 various parameters are studied to optimize the extraction conditions. the molar absorptivity is found to increase from ...
Definition Logical database design is the process of transforming (or mapping) a conceptual schema of the application domain into a schema for the data model underlying a particular DBMS, such as the relational or objectoriented data model. This mapping can be understood as the result of trying to achieve two distinct sets of goals: (i) representation goal: preserving the ability to capture and...
Recently XML is the standard format used for the exchange of data between information systems and is also frequently applied as a logical database model. If we use XML as a logical database model we need a conceptual model for the description of its semantics. However, XML as a logical database model has some special characteristics which makes existing conceptual models as E-R or UML unsuitabl...
Use of state-based models to represent artifact behaviors at conceptual design is a challenging area for design research. Conceptual design of mechatronic systems needs a multi-domain approach in which the “logical behavior” of a mechatronic design artifact is described without any physical realization. This paper presents a case study on state-based representation for the intended behavior of ...
in this thesis, we exploit a simple and suitable method for immobilization of copper(ii) complex of 4?-phenyl-terpyridine on activated multi-walled carbon nanotubes [amwcnts-o-cu(ii)-phtpy]. this nanostructure was characterized by various physico-chemical techniques. to ensure the efficiency and fidelity of copper species, the implementation of three-component strategies in click-chemistry all...
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