Graphical presentation of boolean expressions in a database query language: design notes and an ergonomic evaluation

Abstract

A new query language designed to improve ease-of-use and ease-of-learning for ‘naive’ users is presented. Its main interest is to avoid the explicit use of boolean operators for set operations by pointing on Venn diagrams. A human factors comparison with a more traditional design has been performed, using a query writing task. Results show that graphic representation of selected subsets allows less error-prone queries in a single relation database.     

Spatial SQL: a query and presentation language

Recently, attention has been focused on spatial databases, which combine conventional and spatially related data, such as geographic information systems, CAD/CAM, or VLSI. A language has been developed to query such spatial databases. It recognizes the significantly different requirements of spatial data handling and overcomes the inherent problems of the application of conventional database query languages. The spatial query language has been designed as a minimal extension to the interrogative part of SQL and distinguishes from previously designed SQL extensions by: the preservation of SQL concepts; the high-level treatment of spatial objects; and the incorporation of spatial operations and relationships. It consists of two components, a query language to describe what information to retrieve and a presentation language to specify how to display query results. Users can ask standard SQL queries to retrieve nonspatial data based on nonspatial constraints, use Spatial SQL commands to inquire about situations involving spatial data, and give instructions in the Graphical Presentation Language, GPL to manipulate or examine the graphical presentation     

Generalized Query-By-Rule: a heterogeneous database query language

This paper describes the design and implementation of a high-level query language called Generalized Query-By-Rule (GQBR) which supports retrieval, insertion, deletion and update operations. This language, based on the formalism of database logic, enables the users to access each database in a distributed heterogeneous environment, without having to learn all the different data manipulation languages. The compiler has been implemented on a DEC 1090 system in Pascal.     

Semantic interpretation of a database query language

In this paper, we will discuss a system that semantically interprets a formal database accessing language and generates natural language from this interpretation. In the past, the major way of communication between a user and a database was by means of a formal language. One such language is the SQL query language. Even though constructed as a user friendly language, SQL exemplifies the same difficulties for users as do other formal languages, namely a fairly rigid syntax, the necessity of variable binding, the lack of pronouns, and in the case of erroneous queries error messages that do not provide much insight. To alleviate some of the formal language problems, yet utilize the power of the formal language, we set out to build a natural language ‘umbrella’ for the SQL user. Our goal was not to build a natural language query system, but rather to use semantic knowledge and natural language for paraphrasing the formal language (SQL) and producing error messages as a feedback mechanism. In this way we build a genuine help facility, which would not only aid the user in dealing with SQL, but also trap erroneous queries.     

Natural language query processing in a temporal database

This paper addresses some of the issues that arise in representing temporal information in the database context. It deals not only with the explicit representation of temporal information but with mechanisms for reasoning with it as well. It addresses the issue of processing natural language queries with explicit temporal references. The three issues of knowledge representation, natural language processing and query processing are addressed using the axiomatic framework based on equational logic.     

Two-dimensional specification of universal quantification in agraphical database query language

A technique is proposed for specifying universal quantification and existential quantification (combined with negation) in a two-dimensional (graphical) database query language. Unlike other approaches that provide set operators to simulate universal quantification, this technique allows a direct representation of universal quantification. Syntactic constructs for specifying universal and existential quantifications, two-dimensional translation of universal quantification to existential quantification (with negation), and translation of existentially quantified two-dimensional queries to relational queries are presented. The resulting relational queries can be processed directly by many existing database systems. The authors claim that this technique renders universal quantifications easy to understand. To substantiate this claim, they provide a simple, easy-to-follow guideline for constructing universally quantified queries     

Access数据库中总计查询的教学设计

总计查询是Access数据库教学的重点。针对总计查询中容易混淆的知识点,给出了一些教学案例,并且对教学案例进行了分析,介绍了总计查询的教学设计过程。实践证明,这些教学案例能够提高总计查询的教学效果。     

Access数据库中交叉表查询的教学设计

交叉表查询是Access数据库教学的难点.为此,提出了采用阶梯式教学法和对比的方法,设计适当的教学案例,给出交叉表查询的教学设计过程.实践表明,这种教学设计能够提高教学效果.     

An ergonomic design and performance evaluation of pipettes

This paper describes the results of an investigation of the differences in performance, postures, strains on hand–arm–shoulder musculature, and subjective ratings of three pipettes (models A, B, and C). Both models A and B were pipettes available on the market. Model C was developed for this study of an ergonomically designed pipette. The gripping posture of the three models was distinct both in the anatomical and in the functional sense. Working with models A and B required a four-finger grasp with a thumb operated plunger. Model C required a finger–palmar power grip and the plunger was operated by the fingers. Performance evaluation of the different pipettes in different tasks indicated that using the proposed model C resulted in a 2–3% lower fault rate, a 10% shorter completion time, and the highest subjective ratings among the three. Postural analysis results indicated that when using model C, the shoulder was the least abducted, the wrist was the least extended, and the wrist was the least radially extended. Model C appeared to provide the greatest opportunity for delicate adjustments of posture in response to the activity of the skin receptors and reduced the strains on the upper body musculature, justifying the ergonomic input into the design.     

Emotional facial expressions in synthesised sign language avatars: a manual evaluation

This research explores and evaluates the contribution that facial expressions might have regarding improved comprehension and acceptability in sign language avatars. Focusing specifically on Irish sign language (ISL), the Deaf (the uppercase “D” in the word “Deaf” indicates Deaf as a culture as opposed to “deaf” as a medical condition) community’s responsiveness to sign language avatars is examined. The hypothesis of this is as follows: augmenting an existing avatar with the seven widely accepted universal emotions identified by Ekman (Basic emotions: handbook of cognition and emotion. Wiley, London, 2005) to achieve underlying facial expressions will make that avatar more human like and improve usability and understandability for the ISL user. Using human evaluation methods (Huenerfauth et al. in Trans Access Comput (ACM) 1:1, 2008), an augmented set of avatar utterances is compared against a baseline set, focusing on two key areas: comprehension and naturalness of facial configuration. The approach to the evaluation including the choice of ISL participants, interview environment and evaluation methodology is then outlined. The evaluation results reveal that in a comprehension test there was little difference between the baseline avatars and those augmented with emotional facial expression. It was also found that the avatars are lacking various linguistic attributes.     

Optimizing the evaluation of calculus expressions in a relational database system

There is an interesting search strategy (due to James B. Rothnie) for efficient implementation of a limited kind of selection criterion for a relational database. This strategy is here generalized to arbitrary relational calculus expressions, and an analysis of the resulting improvement of performance is given. The strategy is used in a relational database system TGR and an overview of the architecture of this system is presented. TGR uses microprogrammed database primitives for searching the database. This approach is very similar to the use of a database processor although it also allows flexible change of processor design. The behaviour of TGR in evaluating typical queries is analyzed and the results are used for pointing out the bottlenecks in a relational database system with a particular type of structure. As a conclusion the construction of a database processor with the database primitives from TGR as instruction set is recommended. This would be a step towards getting acceptable performance in a relational database system.     

Formulation of an indirect query processing method for a database computer

Translated from Kibernetika, No. 6, pp. 15–22, November–December, 1988.     

The development and evaluation of an ergonomic glove

The primary intent of this study was to determine if a hand glove could be designed on a criterion of selective protection. Force distribution patterns on the palmar side of hand were obtained from various studies to develop zones of hand that needed protection. A new design for gloves was developed based on the principle of selective protection, where protective material is introduced in varying levels over different parts of the glove, in order to provide protection where it is most needed, and at the same time preserve the desirable dexterity and strength capabilities of the barehand, optimizing the trade-off between protection and performance. Two pairs of prototype gloves incorporating different levels of protection were fabricated and tested using a battery of performance tests and an algometer test for pressure sensitivity. The test battery comprising four dexterity tasks and a maximal voluntary grip strength task was used to assess a number of glove conditions, including the two prototype gloves developed. The results indicate that the performance of the prototype gloves are comparable, and that the performance times for the double glove and the two prototype gloves tested were not significantly different. For the grip strength, the two prototype gloves were better than the double glove. The assembly task performance for the prototype II (laminar glove) was significantly lower than that of the other glove types tested. It appears that gloves of variable thickness can be developed to afford adequate protection at zones of most need. Glove manufacturers are recommended to use an ergonomic approach in the design of gloves. Such an approach, besides protecting the safety objective of gloves, could enhance productivity considerably.     

An ergonomic design and performance evaluation of handy scanners by males

This paper describes the results of an investigation of the difference in performance, posture used, strain on forearm musculature, and subjective ratings of three handy scanners (models A, B and C). Both models A and B were scanners on the market. Model C was developed for validation. The gripping posture of the three models is distinct both in the anatomical and functional sense. Work with model A requires a thumb-forefinger side grip which induces an ulnar deviation angle; work with model B requires a thumb-finger grip; work with model C requires a thumb-finger-palmar grip. Performance evaluation of scanner models A, B and C on different scanning tasks (with and without stitch) using different resolution modes (100 and 400 dpi), indicated that using the proposed model C resulted in a 13% higher success rate, a 14% shorter completion time, the smallest self-selected working area, least strain on the forearm muscles, and highest subjective ratings among the three. Model C appeared to provide the greatest opportunity for delicate adjustments of posture in response to the activity of the skin receptors, justifying the ergonomic input into the design.     

TuLeD (Tupían lexical database): introducing a database of a South American language family

Language Resources and Evaluation - The last two decades witnessed a rapid growth of publicly accessible online language resources. This has allowed for valuable data on lesser known languages to...     

Folding and unfolding manual wheelchairs: an ergonomic evaluation of health-care workers

The objective of this study was to test the hypotheses (i) that health-care workers vary greatly in the methods used to fold and unfold selected manual wheelchairs, and (ii) that many of the methods used include bent and twisted back postures that are known to be associated with a high risk of injury. We studied 20 health-care workers in a rehabilitation center. Subjects folded and unfolded two wheelchairs of cross-brace design, one with and one without a sling seat. As outcome measures, we used a questionnaire, time taken, visual analog scales of perceived exertion and back strain, folded width, videotape and Ovako Working Posture Analysis System (OWAS) back scores (1–4). Subjects used up to 14 different combinations of approach, hand placement and back posture to accomplish the tasks. The mean OWAS scores were in the 2.4–3.1 range and 49 (42%) of the 118 scores recorded were class 4 (back simultaneously “bent and twisted”, considered to be associated with the highest risk of injury). We also observed methods that appeared to be safe and effective. Age, gender, profession, experience and seat condition did not generally influence the outcome measures. We conclude that health-care workers use a variety of methods to fold and unfold wheelchairs, many of which include bent and twisted back postures that may carry a risk of injury. Further study is needed to confirm this risk, to identify more ergonomically sound wheelchair designs and to develop better methods of carrying out the common and important task of folding and unfolding wheelchairs.     

The design and evaluation of a buffer algorithm for database machines

This paper reports on the design, development and evaluation of a buffer algorithm named RESBAL, which exploits parallelism in order to provide high query execution performance in relational database systems. The algorithm aims to provide both predictive and efficient data buffering by exploiting the use of advance knowledge of query reference behaviour. Designed to offer a high level of flexibility, RESBAL employs a multiple buffering strategy both on page fetch level and page replacement level in order to improve buffer performance. The evaluation of RESBAL has been carried out in a parallel database system environment based on a transputer architecture. The results of this performance assessment allow comparison to be made between different buffer algorithms, and demonstrate the feasibility and effectiveness of the RESBAL algorithm. © 1998 John Wiley & Sons, Ltd.     

Development and evaluation of an office ergonomic risk checklist: ROSA--rapid office strain assessment

The Rapid Office Strain Assessment (ROSA) was designed to quickly quantify risks associated with computer work and to establish an action level for change based on reports of worker discomfort. Computer use risk factors were identified in previous research and standards on office design for the chair, monitor, telephone, keyboard and mouse. The risk factors were diagrammed and coded as increasing scores from 1 to 3. ROSA final scores ranged in magnitude from 1 to 10, with each successive score representing an increased presence of risk factors. Total body discomfort and ROSA final scores for 72 office workstations were significantly correlated (R = 0.384). ROSA final scores exhibited high inter- and intra-observer reliability (ICCs of 0.88 and 0.91, respectively). Mean discomfort increased with increasing ROSA scores, with a significant difference occurring between scores of 3 and 5 (out of 10). A ROSA final score of 5 might therefore be useful as an action level indicating when immediate change is necessary. ROSA proved to be an effective and reliable method for identifying computer use risk factors related to discomfort.