New illumination principle for photolithography is investigated. As the optical microlithography approaches its own limit, it becomes apparent that the simple extrapolation of the present technology is not sufficient for the future demands. This paper introduces the new imaging technology that overcomes such a boundary. First, the basic imaging formulae are analyzed and the illumination light is classified into 4 cases. 3-beam case and 2-beam case carry the object information, and the comparison of these 2 cases is carried out theoretically. It can be shown that the 2-beam case has greater depth of focus than that of the 3-beam case, though it has inferior contrast at the best focus. Since this degradation, however, has little effect, the enlargement of the depth of focus can be achieved. In reality, 2-dimensional imaging must be considered. Quadrupole effect can be deduced by the results of the analysis. It shows great improvement in the depth of focus near resolution limit. As it can be applied to the conventional masks, it can be a promising candidate for fhe future lithography. Experimental results are also shown to demonstrate the analysis.

This paper presents a new concept in cryptography called the sibling intractable function family (SIFF) which has the property that given a set of initial strings colliding with one another, it is computationally infeasible to find another string that would collide with the initial strings. The various concepts behind SIFF are presented together with a construction of SIFF from any one-way function. Applications of SIFF to many practical problems are also discussed. These include the hierarchical access control problem which is a long-standing open problem induced by a paper of Akl and Taylor about ten years ago, the shared mail box problem, access control in distributed systems and the multiple message authentication problem.

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.

Progress of speech recognition based on the hidden Markov model has made it possible to realize man-machine dialogue systems capable of operating in real time. In spite of considerable effort, however, few systems have been successfully developed because of the lack of appropriate dialogue models. This paper reports on some of technology necessary to develop a dialogue system with which one can converse comfortably. The emphasis is placed on the following three points: how a human converses with a machine; how errors of speech recognition can be recovered through conversation; and what it means for a machine to be cooperative. We examine the first problem by investigating dialogues between human speakers, and dialogues between a human speaker and a simulated machine. As a consideration in the design of dialogue control, we discuss the relation between efficiency and cooperativeness of dialogue, the method for confirming what the machine has recognized, and dynamic adaptation of the machine. Thirdly, we review the research on the friendliness of a natural language interface, mainly concerning the exchange of initiative, corrective and suggestive answers, and indirect questions. Lastly, we describe briefly the current state of the art in speech recognition and synthesis, and suggest what should be done for acceptance of spontaneous speech and production of a voice suitable to the output of a dialogue system.

In this paper, we investigate the discrepancy between a serial version and a parallel version of zero-knowledge protocols, and clarify the information "leaked" in the parallel version, which is not zero-knowledge unlike the case of the serial version. We consider two sides: one negative and the other positive in the parallel version of zero-knowledge protocols, especially of the Fiat-Shamir scheme.

We studied the manner of clarification and verification in real dialogs and developed a spoken dialog system that can cope with the disambiguation of meanings of user input utterances. We analyzed content, query types and responses of human clarification queries. In human-human communications, ten percent of all sentences are concerned with meaning clarification. Therefore, in human-machine communications, we believe it is important that the machine verifies ambiguities occurring in dialog processing. We propose an architecture for a dialog system with this capability. Also, we have investigated the source of ambiguities in dialog processing and methods of dialog clarification for each part of the dialog system.

Breakdown fields and the charges to breakdown (QBD) of oxides increased after UV/Cl2 pre-oxidation cleaning. This is due to decreased residual metal contaminants on silicon surfaces in the bottom of the LOCOS region after wet cleaning. Treatment in NH4OH, H2O2 and H2O prior to UV/Cl2 cleaning suppressed increases in surface roughness and kept leakage currents through the oxides after UV/Cl2 cleaning as low as those after wet cleaning alone. The large junction leakage currents--caused by metal contaminants introduced during dry etching--decreased after UV/Cl2 cleaning which removes the contaminated layer.

Fabrication of 0.2 to 0.3 µm features is vital for future ultralarge scale integration devices. An area of particular concern is whether optical lithography can delineate such feature sizes, i.e., less than the exposure wavelength. The use of a phase shift mask is one of the most effective means of improving resolution in optical lithography. This technology basically makes use of the interference between light transmitting through adjacent apertures of the mask. Various types of phase shift masks and their imaging characteristics are discussed and compared with conventional normal transmission masks. To apply these masks effectively to practical patterns, a phase shifter pattern design tool and mask repair method must be established. The phase shifting technology offers a potential to fabricate 0.3 µm features by using the current i-line stepper, and 0.2 µm features by using excimer laser stepper.

We show that, if NP language L has an invulnerable generator and if L has an honest verifier standard statistical ZKIP, then L has a 5 move statistical ZKIP. Our class of languages involves random self reducible languages because they have standard perfect ZKIPs. We show another class of languages (class K) which have standard perfect ZKIPs. Blum numbers and a set of graphs with odd automorphism belong to this class. Therefore, languages in class K have 5 move statistical ZKIPs if they have invulnerable generators.

A new direct projection patterning technique of aluminum using synchrotron radiation (SR) is proposed. It is based on the thermal reaction control effect of SR excitation. In the case of the Si surface, pure thermal growth is possible at 200, however, this growth is suppressed perfectly by SR irradiation. On the other hand, Al growth on the SiO2 surface is impossible at the same temperature thermally, however, SR has an effect to initiate thermal reaction. Both new effects of SR, suppression and initiation, are clarified to be caused by atomic order level thin layers formed from CVD gases by SR excitation on the surfaces. By using these effects, the direct inverse and normal projection patterning of Al are successfully demonstrated.

A context-sensitive method to predict linguistic expressions in the next utterance in inquiry dialogues is proposed. First, information of the next utterance, the utterance type, the main action and the discourse entities, can be grasped using a dialogue interpretation model. Secondly, focusing in particular on dialogue situations in context, a domain-dependent knowledge-base for literal usage of both noun phrases and verb phrases is developed. Finally, a strategy to make a set of linguistic expressions which are derived from semantic concepts consisting of appropriate expressions can be used to select the correct candidate from the speech recognition output. In this paper, some of the processes are particularly examined in which sets of polite expressions, vocatives, compound nominal phrases, verbal phrases, and intention expressions, which are common in telephone inquiry dialogue, are created.

A unification-based Japanese parser has been implemented for an experimental Japanese-to-English spoken language translation system (SL-TRANS). The parser consists of a unification-based spoken-style Japanese grammar and an active chart parser. The grammar handles the syntactic, semantic, and pragmatic constraints in an integrated fashion using HPSG-based framework in order to cope with speech recognition errors. The parser takes multiple sentential candidates from the HMM-LR speech recognizer, and produces a semantic representation associated with the best scoring parse based on acoustic and linguistic plausibility. The unification-based parser has been tested using 12 dialogues in the conference registration domain, which include 261 sentences uttered by one male speaker. The sentence recognition accuracy of the underlying speech recognizer is 73.6% for the top candidate, and 83.5% for the top three candidates, where the test-set perplexity of the CFG grammar is 65. By ruling out erroneous speech recognition results using various linguistic constraints, the parser improves the sentence recognition accuracy up to 81.6% for the top candidate, and 85.8% for the top three candidates. From the experiment result, we found that the combination of syntactic restriction, selectional restriction and coordinate structure restriction can provide a sufficient restriction to rule out the recognition errors between case-marking particles with the same vowel, which are the type of errors most likely to occur. However, we also found that it is necessary to use pragmatic information, such as topic, presupposition, and discourse structure, to rule out the recognition errors involved with topicalizing particles and sentence final particles.

We define the communication complexity of a perfect zero-knowledge interactive proof (ZKIP) as the expected number of bits communicated to achieve the given error probabilities (of both the completeness and the soundness). While the round complexity of ZKIPs has been studied greatly, no progress has been made for the communication complexity of those. This paper shows a perfect ZKIP whose communication complexity is 11/12 of that of the standard perfect ZKIP for a specific class of Quadratic Residuosity.

A new optical interconnection system suitable for high-speed ICs using a novel complementary optical interconnection technique has been developed. This system uses paired light sources and photodetectors for optical complementary operation, and greatly lowers the power consumption compared with conventional systems. Analyses and experimental results indicate that this system can operate in the gigabit range, and reduces power consumption to less than 20% of that in conventional systems at 1 Gb/s.

This paper presents two methods for securely realizing caller-authenticated and callee-specified calls over telecommunication networks with terminals that accept IC cards having KPS-based cryptographic functions. In the proposed protocols, users can verify that the partner is the proper owner of a certain ID or a certain pen name. Users' privacy is protected even if they do the caller-authenticated and callee-specified calls and do not pay their telephone charge in advance.

The future trends of optical technologies combined with LSI are reviewed. Present problems of LSI, and the possible solutions to these problems through the merger of the optical technology into LSI are discussed. One of the present trends in interconnection between LSI components is the timeserial approach, originally developed for the optical communication. This method is capable of high speed data transfer. The other is a space-parallel approach, arising from the two-dimensional nature of the light propagation. This approach has the capability of performing parallel processing. A hybrid OEIC, possibly on GaAs, is discussed as an example of future photonic LSI. The lack of key devices is a fundamental barrier to the future improvement of photonic LSI. Direct interaction between photons and electrons is a promissing approach. Some of the Author's ideas to promote the merger of photonics and LSI are proposed.

In this paper, a new scheme for ohrase recognition in conversational speech is proposed, in which prosodic and phonemic information processing are usefully combined. This approach is employed both to produce candidates of phrase boundaries and to discriminate phonemes. The fundamental frequency patterns of continuous utterances are statistically analyzed and the likelihood of the occurrence of a phrase boundary is calculated for every frame. At the same time, the likelihood of phonemic characteristics of each frame can be obtained using a hierarchical clustering method. These two scores, along with lexical and grammatical constraints, can be effectively utilized to develop a possible word sequences or a word lattices which correspond to the continuous speech utterances. Our preliminary experjment shows the feasibility of applying prosody for continuous speech recognition especially for conversational style utterances.

We propose two types of key management systems that use complementary exponential calculation, in which users in the system divide into groups, and the different modulus numbers are assigned to each group and edges between groups. Key generation information over the modulus numbers is issued to a user by a trusted center. The user who receives the information can generate shared encryption keys between users in the system without using key exchange protocol. In our proposed system, the number of primes is one of the parameters for generating key generation information. The number decreases in inverse proportion to the square of the number of groups compared to the original method. Our proposed technique enabled us to extend the number of users in the system to more than one million, which is not possible with the original method.

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 performance of an enciphered B+-tree can be improved by the selective encryption of the components of the nodes in the tree. This paper suggests an approach to the selective encryption of nodes in a B+-tree and a method to substitute the plaintext search keys in order to increase the security of the tree. The method is based on structures in combinatorial block designs, and it allows for faster traversal of the tree, hence improving the overall speed of query responses. It also represents a trade-off between security and performance in that the substitution method affords less security compared to encryption. However, assuming the use of a secure cryptosystem with parameters which are kept secret, the encrypted state of the data pointers and data blocks still prevents an intruder from accessing the stored data. The method based on block designs has the advantage of requiring only a small amount of information being kept secret. This presents a considerable savings in terms of space used to hold security-related information.