We have designed and implemented a simple yet powerful declarative synchronization mechanism for a paralle object-oriented computation model. The mechanism allows the user to control multiple message reception, specify the order of message reception, lock an invocation, and specify relations as invocation constraints. It has been included in a parallel object-oriented language, called A-NETL. The compiler and operating system have been developed on a total architecture, A-NET (Actors NETwork). The experimental results show that (i) the mechanism allows the user to model asynchronous events naturally, without losing the integrity of described programs; (ii) the replacement of the mechanism with the user's code requires tedious descriptions, but gains little performance enhancement, and certainly loses program readability and integrity; (iii) the mechanism allows the user to shift synchronous programs to asynchronous ones, with a scalable reduction of execution times: an average 20.6% for 6 to 17 objects and 46.1% for 65 objects. These prove the effectiveness of the proposed synchronization mechanism.

This paper presents a layered hierarchical switching-software technology, which is based on an object-oriented design approach, that improves software reusability and productivity. This technology enables a non-stop, service-enhanceable software environment (called NOSES), which satisfies customer demands for quick provisioning of new service features without interrupting service, and which improves software reliability. This technology was developed as part of our overall plan to establish a communications software platform that can be customized for use by various communications systems, such as STM, ATM, and IN. The developed non-stop service enhanceable software techniques are call-recovery restart, system file update, and on-line partial file modification; they were achieved by using dynamic program modification. A system file update inevitably affects calls in service, despite efforts to save in-service calls by copying the call data from the old file to the new one. We have therefore developed a different approach: on-line partial-file modification. Our prototype switching system has proven the effectiveness of this modification method and has shown that it can cover a limited range of service feature additions (which meets customer demands for quick service provisioning), as well as all bug fixes (which can lead to higher software reliability due to not using conventional machine code for software patching), without interrupting service. This paper describes on-line partial-file modification, which can be applied to communications systems that require resident program modification or initialization without program loading; that is, the program exists permanently in main memory. An evaluation of this approach also showed that the productivity of service-layer software increases about two times and that the total increase in systems development productivity is about 25%.

We propose an objective measure from assessing low-rate coded speech. The model for this objective measure, in which several known features of the perceptual processing of speech sounds by the human ear are emulated, is based on the Hertz-to-Bark transformation, critical-band filtering with preemphasis to boost higher frequencies, nonlinear conversion for subjective loudness, and temporal (forward) masking. The effectiveness of the measure, called the Bark spectral distortion rating (BSDR), was validated by second-order polynomial regression analysis between the computed BSDR values and subjective MOS ratings obtained for a large number of utterances coded by several versions of CELP coders and one VSELP coder under three degradation conditions: input speech levels, transmission error rates, and background noise levels. The BSDR values correspond better to MOS ratings than several commonly used measures. Thus, BSDR can be used to accurately predict subjective scores.

This paper describes the design of the reflective concurrent object-oriented specification language RMondel. RMondel is designed for the specification and modeling of distributed systems. It allows the development of executable specifications which may be modified dynamically. Reflection in RMondel is supported by two fundamental features that are: Structural Reflection (SR) and Behavioral Reflection (BR). Reflection is the capability to monitor and modify dynamically the structure and the behavior of the system. We show how the features of the language are enhanced using specific meta-operations and meta-objects, to allow for the dynamic modification of types (classes) and instances using the same language. RMondel specification can be modified by adding or modifying types and instances to get a new adapted specification. Consistency is checked dynamically at the type level as well as at the specification level. At the type level, structural and behavioral constrations are defined to preserve the conformance of types. At the specification level, a transaction mechanism and a locking protocol are defined to ensure the consistency of the whole specification.

This paper presents a method for spatial and temporal segmentation of long image sequences which include multiple independently moving objects, based on the Minimum Description Length (MDL) principle. By obtaining an optimal motion description, we extract spatiotemporal (ST) segments in the image sequence, each of which consists of edge segments with similar motions. First, we construct a family of 2D motion models, each of which is completely determined by its specified set of equations. Then, based on these sets of equations we formulate the motion description length in a long sequence. The motion state of one object at one moment is determined by finding the model with shortest description length. Temporal segmentation is carried out when the motion state is found to have changed. At the same time, the spatial segmentation is globally optimized in such a way that the motion description of the entire scene reaches a minimum.

In this paper, we describe a worst-case design optimization approach for statistical design of integrated circuits with a circuit performance model scheme. After formulating worst-case optimization to an unconstrained multi-objective function minimization problem, a new objective function is proposed to find an optimal point. Then, based on an interpolation model scheme of approximating circuit performance, realistic worst-case analysis can be easily done by Monte Carlo based method without increasing much the computational load. The effectiveness of the presented approach is demonstrated by a standard test function and a practical circuit design example.

A highly reliable, operated efficiently, and scalable switching node is required for multivendor system management networks. This paper presents techniques for applying the Telecommunications Management Network (TMN) concept to a distributed switching node. First, we select the TMN protocol structures so as to minimize the command response time. To ensure efficient operation and flexible design of the operation, administration and maintenance (OA & M) software, we propose a command-message handling function for mapping managed objects (MOs) to the OA & M software. We have designed MO classes for switching-system-specific devices with a redundant configuration that ensures highly reliable system operation. The feasibility of these techniques have been confirmed on a prototype system.

Managed Objects (MOs) can be specified by the combination of a static information model and a dynamic process model. First, this paper presents a mapping of attributes from a process model diagram to an information model diagram. Then, it introduces a concept of topology into these two models and proposes a hypothesis about the relationship of topology in these two models. To explicitly explain the hypothesis, it can be stated that all attributes of incoming or outgoing data related to a process in a process model are mapped to an information model where these attributes are interconnected by an explicit relationship which corresponds to a specific meaning, such as physical containment or logical connection. From an intuitive perspective, it can be said that if two attributes have a close topological relationship in a process model, the mapped attributes also have a close topological relationship in an information model. This hypothesis provides clues for determining whether there is an error in an attribute either in the process model or in the information model. By examining the way attributes of incoming or outgoing data related to a process are mapped to an information model, we can detect whether there is an error with respect to the process. The error correction is performed with the assistance of probability analysis. The method of error detection and correction can be implemented in a computer aided tool. Then, error detection on the attribute level becomes automatic, and error correction on the attribute level becomes interactive through the computer aided tool. Finally, the validity of the hypothesis is confirmed by analyzing ITU-T Recommendation M.3100. The specification of the fabric object class defined in M.3 100 is transformed into these two models and the hypothesis is validated for the analysis of the mapping between these two models.

Considering the trend towards adopting high efficiency picture coding schemes into digital broadcasting services, we investigate objective picture quality scales for evaluating digitally encoded still and moving pictures. First, the study on the objective picture quality scale for high definition still pictures coded by the JPEG scheme is summarized. This scale is derived from consideration of the following distortion factors; 1) weighted noise by the spatial frequency characteristics and masking effects of human vision, 2) block distortion, and 3) mosquito noise. Next, an objective picture quality scale for motion pictures of standard television coded by the hybrid DCT scheme is studied. In addition to the above distortion factors, the temporal frequency characteristics of vision are also considered. Furthermore, considering that all of these distortions vary over time in motion pictures, methods for determining a single objective picture quality value for this time varying distortion are examined. As a result, generally applicable objective picture quality scale is obtained that correlates extremely well with subjective picture quality scale for both still and motion pictures, irrespective of the contents of the pictures. Having an objective scale facilitates automated picture quality evaluation and control.

This paper first proposes an object-oriented service network model, which is composed of application, server and resource object groups, from both viewpoints of rapid and smooth introduction and effective execution of the next generation IN services. The paper also, proposes a testbed system, which is referred to as "To-be-IN (Testbed on Object-oriented and B-ISDN Environment for IN)", for evaluating network architecture based on the proposed model. Using the testbed, several technical issues can be solved such as object-oriented realization of IN services, a provision of distribution transparent environment and a transition strategy from today's IN network. The testbed system is constructed on a currently available computing environment in which a distribution transparency mechanism is added. This system provides Service Creation Environment (SCE) for a purpose of achieving seamless software transfer from a development phase to an operation phase in the object-oriented service network model. The paper finally summarizes some results of an experimental implementation of the system.

Telecommunication services are becoming more and more personalized, integrated, and refined. Advanced personal and mobile telecommunication services, intelligent networks, and network management operations require cooperative network-wide distributed processing on a very large scale. Telecommunication programs must support these services with great flexibility, efficiency, and reliability. This paper proposes a new call processing model that improves the availability and flexibility of telecommunication programs. It first points out requirements, outlines the distributed processing platform PLATINA, and discusses several approaches to the enhanced call processing model. Then it explains the call processing program structure, and gives illustrations of mobile and multi- party service control as typical examples. The Caller-Callee decomposition reduces the complexity of the call processing program and enhances the call model; the separation of call and bearer enhances service flexibility and integration; distributed object-oriented techniques meet software evolution requirements. A prototype program has been implemented and has proved the effectiveness of this approach.

This paper describes two main technologies for achieving reliable real-time distributed communications systems. One is the technology to prevent the influence of a fault in an autonomous distributed system from spreading to the whole system (called autonomous distributed system control). The other is a software structure based on distributed processing, the object-oriented approach, and layering for better maintainability and expandability (called OO software structure). For the autonomous distributed system control, several inter-subsystem communication methods are proposed and evaluated. From the standpoints of the fault processing and processing load, frames should be sent through a data link over ATM connection and when a fault occurs the link should be switched over without loss of data. A pilot system achieved good reliability without an excessive number of dynamic steps. This autonomous control method will lead to a highly reliable communications system with large capacity. For the OO software structure, this paper gives experimental results from the implementation of a prototype system. Its distributed environment should lead to high reliability by extending the CHILL run-time routine (RTR). This software structure promises to provide service quickly, to reduce costs, and to make the development of each layer's software independent. A real-time OS, e.g., CTRON kernel combined with RTR can give real-time performance, high reliability and high productivity over the distributed system. The use of RTR can reduce the time for the call recovery process.

We present a novel algorithm to reconstruct the refractive-index profile of a circularly symmetric object from measurements of the electromagnetic field scattered when the object is illuminated by a plane wave. The reconstruction algorithm is besed on an iterative procedure of matching the scattered field calculated from a certain refractive-index distribution with the measured scattered field on the boundary of the object. In order to estimate the convergence of the reconstruction, the mean square error between the calculated and measured scattered fields is introduced. It is shown through reconstructing several examples of lossy dielectric cylinders that the algorithm is quite stable and is applicable to high-contrasty models in situations where the Born approximation is not valid.

The prediction of a relay contact's life is still very important for support and maintenance of the Crossbar Switching Systems. It was found through surveys and experiments that the protected shower arc is the main reason for switching-relay contact erosion at existing Crossbar Switching Systems, if the contacts were not heavily activated. If the contacts were heavily activated, a long sustained steady arc might occur and severely erode the contacts. This paper proposes an arch energy estimation method for the prediction of contact erosion using object-oriented simulation technology when a steady arc occurs at protected contacts. The arc energy is expressed in a simulation model through analysis, and the model was confirmed through experimentation. The simulation model was used for building block programs of an expert system to predict the life span of switching relays in the existing Crossbar Switching Systems.

ISO and ITU-T have developed the standard concept of the Telecommunications Management Network (TMN). This standard does not, however, specify interface implementation. The user requires an Application Programming Interface (API) that bridges user application and the TMN concept to construct a TMN-based application. This paper proposes an object oriented API (OOAPI) that is suitable for TMN-based operations system implementation. OOAPI is one interface of the Common Management Information Service Element (CMISE), and uses the Common Management Information Protocol (CMIP). OOAPI is composed of two C++ programming language constructs: Data Object and Interface object "M_User". The Data Object makes it easier for the user to access management information. The M_User provides a connection-less CMISE interface because the OOAPI handles CMIP association automatically. The M_User also provides MO location-transparency by using the OSI Directory Service. This paper compares the existing MO location-transparency schemes with the OOAPI method, and clarifies the advantages of OOAPI. This paper also indicates results from OOAPI trials, and confirms that OOAPI has sufficient performance to implement highly effective TMN operations system.

For a complex object model, a form of range restriction called specialization constraint (SC), has been proposed, which is associated not only with the properties themselves but also with property value paths. The domain and range of an SC, however, were limited to single classes. In this paper, SCs are generalized to have sets of classes as their domains and ranges. Let Σ be a set of SCs, where each SC in Σ has a set of classes as its domain and a non-empty set of classes as its range. It is proved that an SC is a logical consequence of Σ if and only if it is a finite logical consequence of Σ. Then a sound and complete axiomatization for SCs is presented. Finally, a polynomial-time algorithm is given, which decides whether or not an SC is a logical consequence of Σ.

This paper addresses a method for constructing surface representation of 3D structures from a sequence of cross-sectional images. Firstly, we propose cell-boundary representation, which is a generalization of PVP method proposed by Yun and Park, and develop an efficient surface construction algorithm from a cell-boundary. Cell-boundary consists of a set of boundary cells with their 1-voxel configurations, and can compactly describe binary volumetric data. Secondly, to produce external surface from the cell-boundary representation, we define 19 modeling primitives (MP) including volumetric, planar and linear groups. Surface polygons are created from those modeling primitives using a simple table look-up operation. Since a cell-boundary can be obtained using only topological information of neighboring voxels, there is no ambiguity in determining modeling primitives which may arise in PVP method. Since our algorithm has data locality and is very simple to implement, it is very appropriate for parallel processing.

A two-dimensional quasi-exact active imaging method for detecting the conducting objects buried in a dielectric half-space is proposed. In this imaging method, an image function which is a projection of buried object to an arbitrary direction, is introduced exactly by taking account of the presence of the planar boundary. The image function is synthesized from the scattering fields which are measured by moving a transmitting antenna (a current source) and a receiving antenna (an observation point) simultaneously along the ground surface. The scattering field is generated by the physical optics current assumed on the surface of buried object. Because the effectiveness of physical optics approximation has been confirmed for this problem, this is a quasi-exact active imaging method. The validity of this imaging method is confirmed by some numerical simulations and an experiment.

This paper presents a new high-speed three-dimensional (3-D) object recognition system based on two-dimensional (2-D) chain code matching. An observed 3-D object is precisely represented by a 2-D chain code sequence from the discrete surface points of the 3-D object, so that any complex objects can be recognized precisely. Moreover, the normalization procedures such as translation, rotation of 3-D objects except scale changes can be performed systematically and regularly regardless of the complexity of the shape of 3-D objects, because almost all the normalization procedures of 3-D objects are included in the 2-D chain code matching procedure. As a result, the additional normalization procedure become only the processing time for scale changes which can be performed easily by normalizing the length of the chain code sequence. In addition, the fast fourier transformation (FFT) is applicable to 2-D chain code matching which calculates cross correlation between an input object and a reference model, so that very fast recognition is performed. In fact, it is demonstrated that the total recognition time of a 3-D ofject is estimated at 5.35 (sec) using the 28.5-MIPS SPARC workstation.

Behavior modeling of objects is critical in object-oriented design. In particular, it is essential to preserve integrity constraints on object behavior in application environments where objects of various classes dynamically interact with each other. In order to provide a stable design technique, a behavior model using the notion of the life cycle schema of a class is proposed. To model the aspect of behavioral abstraction of objects, the notion of schema refinement together with a diagrammatic representation technique is also defined. In this framework, a formalization of behavior constraints on objects which interact with each other is proposed together with its graphical representation. Verification rules of consistency of behavior constraints are also discussed. In order to perform certain functions, several partner objects of the same or different classes should collaborate establishing client-server relationships. The contract of a class is defined as a collection of responsibilities of a server class to a client class where each responsibility is specified in the form of the script. To achieve a high degree of systems integrity, a procedure to derive scripts from behavior constraints on collaborating partners is developed. It is also critical to evenly distribute responsibilities to partner objects. A delegation is placing a whole or a part of responsibilities of an object in charge of other objects. Based on the design principle delegation along the aggregation hierarchy,' a unified design approach to delegation that enables to reorganize scripts in constraints preserving way is proposed.