The Berkeley UNIX Consultant Project

UC (UNIX Consultant) is an intelligent, natural-language interface thatallows naive users to learn about the UNIX operating system. UC wasundertaken because the task was thought to be both a fertile domain forArtificial Intelligence research and a useful application of AI work inplanning, reasoning, natural language processing, and knowledgerepresentation. The current implementation of UC comprises the followingcomponents: A language analyzer, called ALANA, that produces arepresentation of the content contained in an utterance; aninference component called a concretion mechanism that furtherrefines this content; a goal analyzer, PAGAN, that hypothesizes theplans and goals under which the user is operating; an agent, calledUCEgo, that decides on UC's goals and proposes plans for them; adomain planner, called KIP, that computes a plan to address the user'srequest; an expression mechanism, UCExpress, that determines thecontent to be communicated to the user, and a language productionmechanism, UCGen, that expresses UC's response in English. UC alsocontains a component called KNOME that builds a model of the user'sknowledge state with respect to UNIX. Another mechanism, UCTeacher,allows a user to add knowledge of both English vocabulary and factsabout UNIX to UC's knowledge base. This is done by interacting with theuser in natural language. All these aspects of UC make use of knowledgerepresented in a knowledge representation system called KODIAK. KODIAKis a relation-oriented system that is intended to have widerepresentational range and a clear semantics, while maintaining acognitive appeal. All of UC's knowledge, ranging from its most generalconcepts to the content of a particular utterance, is represented inKODIAK.     

Strategies for Expressing Concise, Helpful Answers

An intelligent help system needs to take into account the user's knowledgewhen formulating answers. This allows the system to provide more conciseanswers, because it can avoid telling users things that they already know.Since these concise answers concentrate exclusively on pertinent newinformation, they are also easier to understand. Information about theuser's knowledge also allows the system to take advantage of the user'sprior knowledge in formulating explanations. The system can provide betteranswers by referring to the user's prior knowledge in the explanation(e.g., through use of similes). This process of refining answers is calledanswer expression.The process of answer expression has been implemented in the UCExpresscomponent of UC (UNIX Consultant), a natural language system that helps theuser solve problems in using the UNIX operating system. UCExpress separatesanswer expression into two phases: pruning and formatting.In the pruning phase, subconcepts of the answer are pruned by being markedas already known by the user (and hence do not need to be generated), ormarked as candidates for generating anaphora or ellipsis (since they arepart of the conversational context). In the formatting phase, UCExpressuses information about the user's prior domain knowledge to select amongspecialized expository formats,such as similes and examples, for expressing information to the user. Theseformats allow UCExpress to present different types of information to theuser in a clear, concise manner. The result of UCExpress' answer expressionprocess is an internal form that a tactical level generator can easily useto produce good English.     

User modeling in dialog systems: Potentials and hazards

In order to be capable of exhibiting a wide range of cooperative behavior, a computer-based dialog system must have available assumptions about the current user's goals, plans, background knowledge and (false) beliefs, i.e., maintain a so-called user model. Apart from cooperativity aspects, such a model is also necessary for intelligent coherent dialog behavior in general. This article surveys recent research on the problem of how such a model can be constructed, represented and used by a system during its interaction with the user. Possible applications, as well as potential problems concerning the advisability of application, are then discussed. Finally, a number of guidelines are presented which should be observed in future research to reduce the risk of a potential misuse of user modeling technology.     

A graphical user interface server for unix

The UNIX operating system has attained widespread popularity because of its power, flexibility and elegance. However, the common user interfaces (shells) have been criticized as being cryptic and difficult to use, especially for novices. In this paper, we present a user interface server that can be used to provide a graphical shell for UNIX. This shell helps to overcome a number of difficulties faced by both novices and experts. Although it is largely intended to assist novices, it is also designed not to become a hindrance for expert users and does not sacrifice the basic power and flexibility of UNIX. The server is designed to augment rather than replace text-based interfaces and can be used from a variety of different interactive programs in addition to shells.     

Mach的I／O系统

ＭａｃｈＩ／Ｏ系统采用了和ＵＮＩＸ完全不同的概念和结构。Ｍａｃｈ设备管理围绕端口和存储对象这两个Ｍａｃｈ基本概念进行,提供了方便的ＰＲＣ用户界面。Ｍａｃｈ３．０的Ｉ／Ｏ系统新进展将Ｉ／Ｏ管理作为用户Ｓｅｒｖｅｒ对待。本文介绍了Ｍａｃｈ设备管理机制、“设备独立”的驱动程序的构造原理及其例子、在用户空间对设备的直接控制方法和引进新概念后设备管理的性能情况。     

Planning Intelligent Responses in a Natural Language System

Intelligent help systems cannot merely respond passively to the user'scommands and queries. They need to be able to volunteer information,correct user misconceptions, and reject unethical requests when appropriate.In order to do these things, a system must be designed as an intelligentagent. That is, a system needs to have its own goals and then plan forthese goals. A system which did not have its own goals would never refuseto help users perform unethical actions.Such an intelligent agent has been implemented in the UCEgo component of UC(Wilensky et al. 1984; Wilensky et al. 1988) (UNIX Consultant), a natural languagesystem that helps the user solve problems in using the UNIX operatingsystem. UCEgo provides UC with its own goals and plans. By adoptingdifferent goals in different situations, UCEgo creates and executesdifferent plans, enabling it to interact appropriately with the user.UCEgo adopts goals when it notices that the user either lacks necessaryknowledge, or has incorrect beliefs. In these cases, UCEgo plans tovolunteer information or correct the user's misconception as appropriate.These plans are pre-stored skeletal plans that are indexed under the types ofsituations in which they are typically useful. Plan suggestion situationsinclude the goal which the plan is used to achieve, the preconditions of theplan, and appropriateness conditions for the plan. Indexing plans bysituations improves efficiency and allows UC to respond appropriately to theuser in real time.Detecting situations in which a plan should be suggested or a goal adoptedis implemented using if-detected daemons. These daemons provide asingle mechanism which can be used both for detecting goals and suggestingplans. Different methodologies for the efficient implementation ofif-detected daemons are discussed.     

User Modeling for Personalized City Tours

Several current support systems for travel and tourism are aimed at providing information in a personalized manner, taking users' interests and preferences into account. In this vein, personalized systems observe users' behavior and, based thereon, make generalizations and predictions about them. This article describes a user modeling server that offers services to personalized systems with regard to the analysis of user actions, the representation of assumptions about the user, and the inference of additional assumptions based on domain knowledge and characteristics of similar users. The system is open and compliant with major standards, allowing it to be easily accessed by clients that need personalization services.     

Plan Realization for Complex Command Interaction in the UNIX Help Domain

Yucca-* is a consultation system which is designed to provide the UNIX user, through a friendly interface, with detailed expert advice on the use of the UNIX command language. One of the principal design goals of this system is the ability to provide correct responses to technically complex queries whose solution may involve the interconnection of several commands, each with multiple options. The realization of such a goal requires two things. First, representation of dynamic knowledge about command behavior at a sufficient level of detail to support solution of the query is needed. Second, a planning mechanism capable of interconnecting such knowledge into a cohesive solution must be provided. This paper first develops the command dynamics representation techniques employed in Yucca-*. It then examines in detail the plan generation mechanism which is used to solve complex dynamic queries. Particular emphasis is placed upon those aspects of the problem which are unique to this particular domain. This revised version was published online in August 2006 with corrections to the Cover Date.     

SUN工作站用户界面的改进

本文以ＳＵＮ工作站为背景，提出了ＮＩＳＸ操作系统用户界面的改进方法，改进后的用户面对初学者是友好的，用户可以根据清晰的命令格式说明和上下文有关的帮助信息。直接操纵ＵＮＩＸ的各种命令。程序设计的基本特点是采用了命令表数据结构和ＳｕｎＶｉｅｗ工具，从而使编程非常容易而且简洁。     

Linux通用访问控制框架的设计

访问控制是用来处理主体和客体之间交互的限制,是安全操作系统最重要的功能之一。Linux系统中所采用的访问控制是传统UNIX的基于访问模式位的单一的自主访问控制,在实现这一功能时,系统的访问控制代码散列在核心中,没有形成统一的访问控制模块和相应的接口,不支持策略与机制的分离,缺乏相应的灵活性、扩充性以及易维护性,无法定制化系统的访问控制策略。而在当前以分布式计算作为主导计算模式的背景之下,Linux系统中原有的访问控制是无法满足信息处理系统的日益多样化安全需求。针对上述Linux系统中访问控制机制的缺陷,该文引入了一种通用的访问控制框架称之为Linux通用访问控制框架。该框架是一种与具体的访问控制策略无关的体系结构,支持系统的访问控制策略和机制的分离,与传统的Linux访问控制相比,它借助于在Linux核心系统中得到广泛应用的框架式抽象数据类型,提供了一个一致的、抽象的访问控制接口从而对多种访问控制策略如强制访问控制、基于角色的访问控制等加以支持。在该框架之下,用户甚至可以提供自己的访问控制策略模块,以获得具有更高的灵活性、扩充性和易维护性的系统访问控制机制。同时,由于该框架的引入,系统的访问控制策略模块可以与系统其它部分相分离,从而有利于系统访问控制的结构化?     

The user modeling shell system BGP-MS

BGP-MS is a user modeling shell system that can assist interactive software systems in adapting to their current users by taking the users' presumed knowledge, beliefs, and goals into account. It offers applications several methods for communicating observations concerning the user to BGP-MS, and for obtaining information on currently held assumptions about the user from BGP-MS. It provides a choice of two integrated formalisms for representing beliefs and goals, and includes several types of inferences for drawing additional assumptions based on an initial interview, observed user actions, and stereotypical knowledge about pre-defined user subgroups. BGP-MS is a customizable software system that is independent from applications, operates concurrently with them, and interacts with them through inter-process communication. For tailoring BGP-MS to a specific application domain, the developer must select those components of BGP-MS that are needed in this domain and fill them with relevant domain-dependent user modeling knowledge. This paper first summarizes the user modeling services that BGP-MS provides to application programs at runtime. It discusses the representational and inferential foundations that determine the scope and the limits of these services, and also gives a detailed example illustrating the interaction between the various system components. It describes interfaces that are available to application developers for tailoring BGP-MS to the specific user modeling needs of their application domains. Finally, it compares the system with all other major user modeling shell systems, and describes a first application that employs BGP-MS for adapting hypertext to users' terminological knowledge.The managing UMUAI editor for this paper was Sandra Carberry, University of Delaware.     

Demonstrating the Cognitive Plausibility of Interactive System Specifications

Much of the behaviour of an interactive system is determined by its user population. This paper describes how assumptions about the user can be brought into system models in order to reason about their behaviour. We describe a system model containing reasonable assumptions about the user as being ‘cognitively plausible’. Before asserting the plausibility of a model however we must first be able to make the assumptions made in that model inspectable. There is a tension between the inspectability of user assumptions and the tractability of models; inspectable models tend to not be very tractable and vice versa. We describe how we can get round this tension, by deriving tractable models from explicit user assumptions. The resulting models may not of themselves be very inspectable to human-factors workers, but the process by which they are derived is inspectable. Hence we claim that we can have both tractability and inspectability. We exemplify our claims using a simple cognitive model and ‘Meeting Maker’, an interactive electronic diary system. Received March 2000 / Accepted in revised form July 2000     

Intelligent Assistance in Authoring Dynamically Generated Web Interfaces

Since its emergence in the early 1990s, the WWW has become not only an information system of unprecedented size, but a universal platform for the development of services and applications. However, most of the advances in web technologies are intended for professional developers, paying poor attention to end-users with no programming abilities but with explicit needs of creating and customizing web-based presentations. This provides a strong motivation for end-users to act as designers at some point, leading to an emerging role of new computing-related professionals to be considered. This paper is an effort to leverage such difficulties by providing intelligent mechanism to assist end-users in web-based authoring tasks. To carry out such a challenge, intelligent user-monitoring techniques are exploited to obtain high-level information that will be used to infer the user’s preferences and assist him throughout the interaction. Furthermore, we report on how iteration patterns can be applied to avoid repetitive tasks that are automatically carried out on behalf of the user. In order to bring off a feasible trade-off between expressivity and ease of use, a user experiment to obtain the user’s perception and evaluate the hit-rate of our system is also presented.     

UNIX系统行为安全特性及其防护研究

基于UNIX操作系统的工作原理,根据UNIX操作系统的行为,该文探讨了系统的安全问题。文章分析了UNIX系统的保护对象,以及影响这些对象安全的因素。研究了系统中根权限的重要性,以及它可能造成系统安全问题的方式。并结合操作系统内核构造,阐述了用户与系统的各种交互方式,而且着重分析了系统在网络中可能暴露的不安全因素。提出了基于UNIX工作原理的一些减小系统安全风险的方法。