Practical linewidth measurement accuracy better than 0.02 µm 3 sigma that meets the production requirement for devices with sub-half micron features, was achieved in a field emission scanning electron-beam metrology system (Hitachi S-7000). In order to establish high accuracy linewidth measurement, it was found in the study that reduction of electron-beam diameter and precise control of operating conditions are significantly effective. For the purpose of reducing electron-beam diameter, a novel electron optical system was adopted to minimize the chromatic aberration which defines electron-beam profile. As a result the electron beam diameter was reduced from 20 nm to 16 nm. In order to reduce measurement uncertainties associated with actual operating conditions, a field emission electron gun geometry and an objective lens current monitor were investigated. Then the measurement uncertainties due to operating conditions was reduced from 0.016 µm to 0.004 µm.

In this paper, a general theory on multiple-valued static random-access-memory (RAM) is investigated. A criterion for a stable and an unstable modes is proved with a strict mathematical method and expressed with a diagrammatic representation. Based on the theory, an NMOS 6-transistor ternary and a quaternary static RAM (SRAM) cells are proposed and simulated with PSPICE. The detail circuit design and realization are analyzed. A 10-valued CMOS current-mode static RAM cell is also presented and fabricated with standard 5-µm CMOS technology. A family of multiple-valued flip-flops is presented and they show to have desirable properties for use in multiple-valued sequential circuits. Both PSPICE simulations and experiments indicate that the general theory presented are very useful and effective tools in the optimum design and circuit realization of multiple-valued static RAMs and flip-flops.

Global dynamic behavior particularly the bifurcation of periodic orbits of a parallel blower system is studied using a piecewise linear model and the one-dimensional map defined by the Poincare map. First several analytical tools are presented to numerically study the bifurcation process particularly the bifurcation point of the fixed point of the Poincare map. Using two bifurcation diagrams and a bifurcation set, it is shown how periodic orbits bifurcate and leads to chaotic state. It is also shown that the homoclinic bifurcations occur in some parameter regions and that the Li & Yorke conditions of the chaotic state hold in the parameter region which is included in the one where the homoclinic bifurcation occurs. Together with the above, the stable and unstable manifolds of a saddle closed orbit is illustrated and the existence of the homoclinic points is shown.

The robust finite settling time stabilization problem is considered for a multivariable discrete time plant with structured uncertainties. Finite settling time (FST) stability of a feedback system is a notion introduced recently for discrete time systems as a generalization of the dead-beat response. The uncertain plant treated in this paper is described by (E0+ΣKi=1qiEi)x(t+1)(A0+ΣKi=1qiAi)x(t)+(B0+ΣKi=1qiBi)u(t), and y(t)=(C0+ΣKi=1qiCi)x(t) where Ei, Ai, Bi and Ci (0iK) are prescribed real matrices and qi (1iK) are uncertain parameters restricted to prescribed intervals [qi, i]. It is shown in this paper that a controller robustly FST stabilizes such an uncertain plant, if, the uncertain plant satisfies some conditions, and the controller simultaneously FST stabilizes a finite set of plants. The result leads to a testable necessary and sufficient condition of the existence of a solution to the robust FST stabilization problem, and a systematic method of designing a robust FST stable feedback system, in the case where the plant contains only one uncertain parameter.

An optimal algorithm for decomposing a special type of the Hasse diagram into a minimum set of disjoint paths is described. It is useful for testing the consistency of functional dependencies.

A simple inequality that guarantees stability of perturbed linear state space models is proposed. It is shown that the result is superior to some existing result in sharpness and possesses some advantageous aspects.

Real-time database systems have the properties of database and real-time systems. This means they must keep timing constraints of transactions as required in real-time systems, and at the same time ensure database consistency as required in database systems. Real-time concurrency control is a general approach for resolving this conflict. In this type of control, a concurrency control technique for database systems is integrated with a task scheduling technique for real-time systems. This paper surveys previous studies on real-time concurrency control and considers future research directions.

A system is constructed for the processing of question-answer dialogue as a subsystem of the speech response device. In order to increase the adaptability to dialogue topics, rules for dialogue processing are classified into three groups; universal rules, topic-dependent rules and task-dependent rules, and example-based description is adopted for the second group. The system is disigned to operate only with information on the content words of the user input. As for speech synthesis, a function is included in the system to control the focal position. Introduction and guidance of ski areas are adopted as the dialogue domain, and a prototype system is realized on a computer. The dialogue example performed with the prototype indicates the propriety of our method for dialogue processing.

The security problems of object-oriented database system are investigated and security level assignment constraints and an access control mechanism based on the multilevel access control security policy are proposed. The proposed mechanism uses the Trusted Computing Base. A unique feature of the mechanism is that security levels are assigned not only to data items (objects), but also to methods and methods are not shown to the users whose security level is lower than that of the methods. And we distinguish between the security level of a variable in a class and that in an instance and distinguish between the level of an object when it is taken by itself and it is taken as a variable or an element of another complex object. All of this realizes the policy of multilevel access control.

The intelligent network services will considerably increase the amount of Control and OAM (Operation, Administration and Maintenance) Information (Ic&o) which will be stored in a huge number of distributed databases. Therefore, the management and the organization of databases have become critical issues for securing network performance. This paper studies one of the IN applications that is likely to be an important user of the Ic&o network, namely the Universal Personal Telecommunication (UPT). UPT enables the personal mobility, based on a UPT number related to the user and not a terminal equipment. The Ic&o information of UPT is carried through an ATM based transport network. Taking two fundamental parameters into consideration, namely delay time and the number of users, and two kinds of data location probabilities, this paper studies two basic procedures for finding target data in UPT databases, i.e., chaining and broadcasting. Results show that, when the data location probability is uniform, the broad-casting mode is the faster mode but, on the other hand, the chaining mode allows a larger number of users because the disk access time is less restrictive than in the broadcasting mode. Moreover, this study shows that increasing the number of databases also increases the allowed number of users up to a specific threshold. With a Broadcast Chaining mode, a better compromise between the delay time and the number of allowed users is obtained. If the probability depends on the location of databases (the probability is conversely proportional to the square of the number of searched databases), the results show that the chaining mode is preferable from both the number of users allowed and the delay time viewpoints. Finally, the implementation aspect is discussed.

A new indexing technique for rapid evaluation of nested query on composite object is propoced, reducing the overall cost for retrieval and update. An extended B+ tree is introduced in which object identifier (OID) to be searched and path information usud for update of index record are stored in leaf node and subleaf node, respectively. In this method, the retrieval oeration is applied only for OIDs in the leaf node. The index records of both leaf and subleaf nodes are updated in such a way that the path information in the subleaf node and OIDs in the leaf node are reorganized by deleting and inserting the OIDs. The techniaue presented offers advantages over currently related indexing techniques in data reorganization and index allocation. In the proposed index record, the OIDs to be reorganized are always consecutively provided, and thus only the record directory is updated when an entire page should be removed. In addition, the proposed index can be allocate to a path with the length greater than 3 without splitting the path. Comparisons under a variety of conditions are given with current indexing techniques, showing improved performance in cost, i.e., the total number of pages accessed for retrieval and update.

The self-checking design using 2-rail logic is one of the most popular design of self-shecking circuits. Even for a self-checking circuit, a test is necessary after VLSI chip or system fabrication, at each time the system is powered, and, under certain circumstances, in the case of maintenance. Therefore, an easy test scheme is desirable for that circuit. A new design method for a 2-rail logic combinational circuit is proposed, where stuck-open and sutck-on faults FETs can be easily detected. In the proposed circuit design, 4 FETs are added to each gate in a conventional 2-rail logic circuit. Two logical gates, DOR and DAND, are also added to the circuit as fault observing gates. Each test consists of a sequence of 3 input vectors, that is, a type of 3-pattern test, ti1ti2ti3. A test can be easily generated and fault observation is easy. Stuck-at fault and stuck-open fault on lines and almost all multiple faults can also be detected by the test. A gate construction method, test generation method, circuit construction method, and several discussions including gate delay increasing are presented.

A film carrier with 48 peripheral-contacts, which is applicable to ultra-high speed GaAs digital integrated circuits (ICs) with a more than 10 Gbps operation, has been developed. The film carrier has been realized using the following newly developed techniques; (1) wave guides with a well-controlled characteristic impedance of 50 Ω, (2) precise vias of as small as 50 µm diameter conducting both sides of grounded metal planes on a polyimide film, and (3) a feed-through structure for high speed input signals with good impedance matching. The film carrier was molded by resin after ILB (inner lead bonding) to a chip with a copper plate heat spreader. As an application, the film carrier has been applied to a 3 Gbps operational 4-bit GaAs multiplexer IC, and has been proved to have excellent high-frequency characteristics.

The problem of presentation view generation over external/conceptual view is discussed for database systems. The presentation view is expressed by a format of a report which is generated as the result of a database query. A new presentation format generation scheme for composite reports is proposed for object-oriented databae systems. The reports can have nested (extended non-first-normal-form) formats. The presentation format should vary at run time, depending on repeating groups and data arrangement. The proposed scheme is based on the idea of dynamic co-referring objects, which uses an object-oriented data model extended to the presentation layer. As important features, various composite reports can be easily derived from databases, and dynamic format modification is possible interactively, even after retrieving the data. The scheme is useful for database applications which require a wide variety of formats for casual queries, where the report generation programming cost will be greatly reduced.

Relational query languages like SQL and QUEL require the users to understand the complex detabase structure. This is a burden on end users, especially novice end users who access the database on a casual and infrequent basis. To alleviate the need to know the logical database origanization, this paper proposes the use of a semantic data model, known as the Enhanced Entity-Relationship (EER) model, as a front-end to the relational systems. A formal, high-level Visual Knowledge Query Language (VKQL) has also been designed for this interface. This language provides for knowledge abstraction as the user communicates only domain knowledge with the system without any implication on the storage structure or search strategies. A translation algorithm is also described in this paper to translate VKQL queries to Standard SQL equivalents.

Based on the Fornasini-Marchesini second model, an efficient algorithm is developed to derive the characteristic polynomial and the inverse of the system matrix from the state-space parameters. As a result, the external description of the Fornasini-Marchesini second model is clarified. A technique for designing 2-D recursive digital filters in the frequency domain is then presented by using the Fornasini-Marchesini second model. The resulting filter approximates both magnitude and group delay specifications and its stability is always guaranteed. Finally, three design examples are given to illustrate the utility of the proposed technique.

The meaning of analogical reasoning in locally stratified logic programs are described by generalized stable model (GSM) semantics. Although studies on the theoretical aspects of analogical reasoning have recently been on the increase, there have been few attempts to give declarative semantics for analogical reasoning. This paper takes notice of the fact that GSM semantics gives meaning to the effect that the negated predicates represent exceptional cases. We define predicates that denote unusual cases regarding analogical reasoning; for example, ab(x)p(x)g(x), where p(s), q(s), p(t) are given. We also add rules with negated occurrences of such predicates into the original program. In this way, analogical models for original programs are given in the form of GSMs of extended programs. A proof procedure for this semantics is presented. The main objective of this paper is not to construct a practical analogical reasoning system, but rather to present a framework for analyzing characteristics of analogical reasoning.

This paper describes the waveform relaxation (WR) algorithm with the under relaxation method based on the virtual state formulation (VSF) technique and the effect of multirate behavior in this algorithm. First, we present the virtual state relaxation method using VSF technique. Next, we introduce the VSF method into WR algorithm in order to exploit the multirate behavior. Furthermore, we construct the relaxation-based circuit simulator DESIRE2 and apply this simulator to the transient analysis of MOS circuits. Finally, we show that the present technique enables to use efficiently the multirate integration method in VSR and reduce the total simulation time without losing the waveform accuracy.

The outputs of all gates in a circuit are assumed to be observable unber the highly observable condition, which is mainly based on the use of E-beam testers. When using the E-beam tester, it is desirable that the test set for a circuit is small and the test vectors in the test set can be applied in a successive and repetitive manner. For a combinational circuit, these requirements can be satisfied by modifying the circuit into a k-UCP circuit, which needs only a small number of tests for diagnosis. For a sequential circuit, however, even if the combinational portion has been modified into a k-UCP circuit, it is impossible that the test vectors for the combinational portion can always be applied in a successive and repetitive manner because of the existence of feedback loops. To solve this problem, the concept of k-UCP scan circuits is proposed in this paper. It is shown that the test vectors for the combinational portion in a k-UCP scan circuit can be applied in a successive and repetitive manner through a specially constructed scan-path. An efficient method of modifying a sequential circuit into a k-UCP scan circuit is also presented.

A tag-partitioned join algorithm is described. The algorithm partitions only one relation, while other partition-based algorithms partition both relations. It is performed as the joinable tuples of one relation are rearranged and some of them are duplicated according to the original sequence of the join attribute values of the other relation. To do this, the algorithm first finds the positions of all the tuples of the other relation which are joinable with each tuple of one relation, and then partitions joinable tuples of one relation into buckets by using the positions found. Final joining is performed on the partitioned relation and the other relation. We analyze and compare the performance of the algorithm with that of other partition-based join algorithms. The comparison shows that our method is better than other partition-based methods under the practical values of the analysis parameters.