Satellite derived crop calendar for canal operation schedule in Bhadra project command area,India

Spatial information on crop calendars in the command areas of irrigation systems is useful to irrigation engineers in order to achieve chronological synchronization between water delivery pattern and crop life cycle. Such synchronization is vital for efficient use of water. The capability of satellite remote sensing technology to generate spatial crop calendar information in an irrigated command area and its usefulness in the evaluation of water delivery patterns are demonstrated in this paper. The study pertains to the major crop paddy during the rabi season (December to June) of 1992-93, in the Bhadra project command area of Karnataka state, India. Analyses of multidate Normalized Difference Vegetation Index (NDVI) profiles of paddy crop generated from Indian Remote Sensing (IRS) satellite data for each distributary command reveal three distinct growth patterns in the study area with each pattern characterized by a particular crop calendar. The spatial variability in crop calendar over the total command area has thus been derived. The ground truth data obtained in crop cutting experiments (CCEs) validate the satellite derived crop calendar. Distributary wise, water delivery data have been studied in conjunction with the satellite derived crop calendar to determine whether the existing pattern of water delivery covers the required length of crop life cycle in the command area. It was found that the water supply was stopped about 30 days before harvesting in some distributaries and in some about 20-30 days before harvesting. A list of distributaries with greater lags between cessation of water supply and crop harvest was provided to irrigation system engineers to aid their plans for providing a reliable and predictable irrigation service. This is possible either through reorganization of canal operation schedule or through educating farmers about the need for adjusting their agricultural activities to match water supply patterns.     

Clustering-Based Visual Interfaces for Presentation of Web Search Results: An Empirical Investigation

The result of a typical web search is often overwhelming. It is very difficult to explore the textual listing of the resulting documents, which may be in the thousands. In order to improve the utility of the search experience, we explore presenting search results through clustering and a zoomable two-dimensional map (zoomable treemap). Furthermore, we apply the fisheye view technique to this map of web search clusters to provide details in context. In this study, we report on our evaluation of these presentation features. The particular interfaces evaluated were: (1) a textual list, (2) a zoomable two-dimensional map of the clustered results, and (3) a fisheye version of the zoomable two-dimensional map where the results were clustered. We found that subjects completed search tasks faster with the visual interfaces than with the textual interface, and faster with the fisheye interface than just the zoomable interface. Based on the findings, we conclude that there is promise in the use of clustering and visualization with a fisheye zooming capability in the exploration of web search results.     

Understanding Calendar Use

This article is an interview study of calendar use and a cognitive analysis of the interactions between the design of calendars and the task of prospective remembering. The study and analysis are coordinated to present a general critique of current electronic calendar designs and to note opportunities for future designs. The interview data reveal continued use of paper calendars in a highly computerized setting. A key conclusion is that paper calendars support prospective remembering by promoting browsing of existing appointments during subsequent calendar keeping but that this advantage is compromised in current electronic designs. Other aspects of the interviews and the analyses address the representational limitations of both paper and electronic calendars. This research explores a methodology in which design implications of qualitative empirical data are understood and systematized through theoretical analyses of existing artifacts.     

Touching annotations: A visual metaphor for navigation of annotation in digital documents

Direct touch manipulation interactions with technology are now commonplace and significant interest is building around their use in the culture and heritage domain. Such interactions can give people the opportunity to explore materials and artefacts in ways that would otherwise be unavailable. These are often heavily annotated and can be linked to a large array of related digital content, thus enriching the experience for the user. Research has addressed issues of how to present digital documents and their related annotations but at present it is unclear what the optimal interaction approach to navigating these annotations in a touch display context might be.In this paper we investigate the role of two alternative approaches to support the navigation of annotations in digitised documents in the context of a touch interface. Through a control study we demonstrate that, whilst the navigation paradigm displays a significant interaction with the type of annotations task performed, there is no discernible advantage of using a natural visual metaphor for annotation in this context. This suggests that design of digital document annotation navigation tools should account for the context and navigation tasks being considered.     

What does it mean to be good at using a mobile device? An investigation of three levels of experience and skill

An increasing number of computer users lack formal training in operating their devices. These daily users cannot be described as novices or experts within the predominant view of expertise. In order to describe and better understand this type of self-taught intermediate level of skill, 10 casual users of a high-end smartphone series were compared to 10 novices and 4 professionals (help desk personnel) in their learning histories, task performance, and cognitive outcomes. Our study suggests that this type of self-taught intermediate level of skill is device-specific. Experienced users (casual users and experts) exhibited superior performance for representative tasks. This is mainly attributable to faster navigation and better knowledge of interface terminology, not to deeper conceptual representation of the problems. Interviews suggest that this skill is the consequence of routine use and three recurring learning events: familiarization, following of media, and ad hoc problem-solving situations. We conclude by discussing why intermediate levels of skill deserve more attention in HCI research.     

Beyond web content accessibility guidelines: Design of enhanced text user interfaces for blind internet users

Websites do not become usable just because their content is accessible. For people who are blind, the application of the W3C's Web Content Accessibility Guidelines (WCAG) often might not even make a significant difference in terms of efficiency, errors or satisfaction in website usage. This paper documents the development of nine guidelines to construct an enhanced text user interface (ETI) as an alternative to the graphical user interface (GUI). An experimental design with 39 blind participants executing a search and a navigation task on a website showed that with the ETI, blind users executed the search task significantly faster, committing fewer mistakes, rating it significantly better on subjective scales as well as when compared to the GUIs from other websites they had visited. However, performance did not improve with the ETI on the navigation task, the main reason presumed to be labeling problems. We conclude that the ETI is an improvement over the GUI, but that it cannot help in overcoming one major weakness of most websites: If users do not understand navigation labels, even the best user interface cannot help them navigate.     

基于图象分层优化二元树结构表示的图象处理基本算法

在图象分层优化二元树结构表示的基础上,给出了图象分层优化二元树结构表示的图象 处理基本算法:点搜索算法、邻域查找算法及同级灰度查找算法,试验结果表明,该结构表示 比线性四元树结构表示及指针四元树结构表示相应算法查找速度要快.     

The Role of Search Result Position and Source Trustworthiness in the Selection of Web Search Results When Using a List or a Grid Interface

Previous research indicates that web users rely to a great extent on the ranking provided by the search engine and predominantly access the first few web pages presented. In case that the information sources presented in the top of the search engine results page (SERP) are of rather low trustworthiness, this might lead to a biased or incomplete view of the topic—especially when dealing with controversial issues. Study 1, thus, systematically investigated whether participants who were asked to search for an unfamiliar and controversial medical issue accessed fewer trustworthy information sources and consequently included less information from trustworthy pages in their argumentation when the search results were ranked from least to most trustworthy on a Google-like SERP than when they were ranked from most to least trustworthy. Results from Study 1 confirmed these assumptions. Furthermore, Study 2 showed that when the same materials were presented in a grid interface, the impact of the position of the search results on their selection was substantially reduced. Irrespective of whether the most trustworthy search results were presented in the top or the bottom row of the grid interface, users predominantly selected the most trustworthy search results from the SERP and included the same amount of information from trustworthy pages in their argumentation.     

基于多层混合结构的IPv6路由表查找算法

针对现有的大多IPv6路由表查找算法采用各种优化手段提高查找性能,却使得路由更新需要重构整个路由表的问题,提出基于多层混合结构的IPv6路由表查找算法。该算法在第一层借鉴最优查找树的优点,把前缀1~16位的不同取值按其在路由表中出现的概率降序存储在线性表中,在第二、三层把前缀的17~32位和33~48位分别用二叉平衡树组织,在第四层把49~64位使用线性表组织。实验结果表明,该算法查找速度快,占用内存少,动态增量更新速度快。     

Web document clustering using a hybrid neural network

The list of documents returned by Internet search engines in response to a query these days can be quite overwhelming. There is an increasing need for organising this information and presenting it in a more compact and efficient manner. This paper describes a method developed for the automatic clustering of World Wide Web documents, according to their relevance to the user’s information needs, by using a hybrid neural network. The objective is to reduce the time and effort the user has to spend to find the information sought after. Clustering documents by features representative of their contents—in this case, key words and phrases—increases the effectiveness and efficiency of the search process. It is shown that a two-dimensional visual presentation of information on retrieved documents, instead of the traditional linear listing, can create a more user-friendly interface between a search engine and the user.     

Using occupancy grids for mobile robot perception and navigation

An approach to robot perception and world modeling that uses a probabilistic tesselated representation of spatial information called the occupancy grid is reviewed. The occupancy grid is a multidimensional random field that maintains stochastic estimates of the occupancy state of the cells in a spatial lattice. To construct a sensor-derived map of the robot's world, the cell state estimates are obtained by interpreting the incoming range readings using probabilistic sensor models. Bayesian estimation procedures allow the incremental updating of the occupancy grid, using readings taken from several sensors over multiple points of view. The use of occupancy grids from mapping and for navigation is examined. Operations on occupancy grids and extensions of the occupancy grid framework are briefly considered     

Integrating multiple calendars using τ ZAMAN

Programmers are increasingly interested in developing applications that can be used internationally. Part of the internationalization effort is the ability to engineer applications to use dates and times that conform to local calendars yet can inter‐operate with dates and times in other calendars, for instance between the Gregorian and Islamic calendars. ZAMAN is a system that provides a natural language‐ and calendar‐independent framework for integrating multiple calendars. ZAMAN performs ‘runtime‐binding’ of calendars and language support. A running ZAMAN system dynamically loads calendars and language support tables from XML‐formatted files. Loading a calendar integrates it with other, already loaded calendars, enabling users of ZAMAN to add, compare, and convert times between multiple calendars. ZAMAN also provides a flexible, calendar‐independent framework for parsing temporal literals. Literals can be input and output in XML or plain text, using user‐defined formats, and in different languages and character sets. Finally, ZAMAN is a client/server system, enabling shared access to calendar servers spread throughout the Web. This paper describes the architecture of ZAMAN and experimentally quantifies the cost of using a calendar server to translate and manipulate dates. Copyright © 2006 John Wiley & Sons, Ltd.     

Expressing Time Intervals and Repetition Within a Formalization of Calendars

We investigate a formal representation of time units , calendars , and time unit instances as restricted temporal entities for reasoning about repeated events. We generalize Allen's interval relations to a class level, and based on interval classes we define time units. We examine characteristics of time units, and provide a categorization of the hierarchical relations among them. Hence we define an abstract hierarchical unit structure (a calendar structure ) that expresses specific relations and properties among the units that compose it. Specific objects in the time line are represented based on this formalism, including nonconvex intervals corresponding to repeated events. A goal of this research is to be able to represent and reason efficiently about repetition in time.     

探析印刷行业中的相关企业分类

自宋代我国毕昇发明活字版印刷术至德国人谷登堡创造铅合金活字版印刷术,时至今天数码印刷技术的出现,印刷行业经历了几世纪的演变积累。从报纸、杂志、地图、海报、广告、信封、信笺、商标到名片、请柬、信用卡、钞票、贺卡、台历、挂历、包装纸盒、装饰壁纸等等都是通过印刷技术呈现的。久而久之,不同的需求就产生了不同的印刷客户。     

Protocol Analysis of a Federated Search Tool: Designing for Users

SUMMARY

Librarians at Springfield College conducted usability testing of Endeavor's federated search tool, ENCompass for Resource Access. The purpose of the testing was to make informed decisions prior to customizing the look and function of the software's interface in order to make the product more usable for their patrons. Protocol, or think-aloud, analysis was selected as a testing and analysis method. Subjects from the general college community were recruited and given a list of tasks to perform on ENCompass, and they were asked to speak all of their thoughts out loud as they worked. Upon analyzing the test results, researchers found that subjects' problems fell into certain categories, such as unfamiliarity with terms or navigation from screen to screen. The researchers were able to use their findings to recommend extensive revisions to the interface, which improved usability for this library's patrons.     

Is visual content in textual search interfaces beneficial to dyslexic users?

Dyslexia is a learning disability characterised by problems with accurate or fluent word recognition, poor decoding, and poor spelling abilities. Although several studies have addressed dyslexia and Web accessibility, less is known about how dyslexia affects information search. This study investigated whether the inclusion of icons in search user interfaces enhances performance among dyslexics. A total of 21 dyslexics and 21 controls completed 52 search tasks in 4 conditions: icons only, words only, and both icons and words in a grid layout and a list layout, while eye movements were recorded. Dyslexics took significantly longer than controls to locate targets in tasks containing text, but not in the icon-only condition. Dyslexics had longer fixation durations than controls in both icon and text based search arrays, suggesting higher mental load associated with search tasks generally. The addition of words to icon arrays led to faster search times within controls, but not dyslexics. Dyslexics also exhibited more fixations on dual-modality tasks, and longer scanpaths than controls in list layout. Both groups were fastest searching the list layout, with icons and words listed in columns. Results are discussed in terms of the design of accessible search interfaces for dyslexic users, taking into account mental load of dual-modality information display, and the arrangement of search items. Empirical data is provided for the design of accessible search results interfaces for dyslexics.     

The effects of 3D interface metaphor on older adults’ mobile navigation performance and subjective evaluation

Navigating vast information spaces through mobile interfaces has become a common activity in older adults' everyday lives. Studies suggested that interface metaphors could be used to facilitate users' metal model development and information processing when using mobile technologies. However, we know little about how metaphors affect older adults' mobile navigation behavior, and which user characteristics matter during this perceptual and cognitive process. To investigate this, a card interface with a 3D metaphor and a list interface without 3D metaphors were compared among twenty-two participants when performing four navigation tasks. User characteristics including demographic factors, technology experience, and user capabilities were examined. The participants' navigation performance and subjective evaluations were measured as the dependent variables. From the results, we recommend the list interface without 3D metaphors as a beneficial choice for older adults. It performed better in navigation performance, although the differences are not statistically significant. Moreover, navigation performance using the card interface with a 3D metaphor was significantly associated with participants' perceptual speed, thus this interface may be more sensitive to capability declines. Valuable insights into the older adults’ mobile navigation performance and preferences are discussed and important implications for the design of mobile navigation user interfaces are proposed based on the results.Relevance to industryThe experimental results propose a more beneficial way to present contents on a mobile user interface for older adults and provide valuable insights for the designers and industry to help them understand the older adults’ usage and perceptions towards the application of 3D metaphors when navigating with mobile interfaces.     

An Algebraic Representation of Calendars

This paper uses an algebraic approach to define temporal granularities and calendars. All the granularities in a calendar are expressed as algebraic expressions based on a single bottom granularity. The operations used in the algebra directly reflect the ways with which people construct new granularities from existing ones, and hence yield more natural and compact granularities definitions. Calendar is formalized on the basis of the algebraic operations, and properties of calendars are studied. As a step towards practical applications, the paper also presents algorithms for granule conversions between granularities in a calendar.     

Effect of Web navigation style in elderly users

The population is gradually aging, but only 4% of elderly people are Internet users. These data indicate the need to take action to bridge this digital divide.Several studies show that learning and memory processes are faster when there is familiarity with the learning object, and the user finds a clear internal correspondence between the previous experience and the current experience. The elderly make up one of the groups most affected by the digital divide, with less Internet access, knowledge, and use. The Internet is by definition an almost infinite structure of hypertext, where the user navigates by using information in an active way, and where the elderly lack previous experience with hypertextual applications. The aim of this study is to test the navigation variable by comparing two designs of the same email Web application with different navigation styles: linear vs hypertextual navigation.The study consisted of usability testing, employing the method of task analysis. Other assessment tools were also used, such as the eye tracker and post-session self-report questionnaires designed ad hoc for this study.A sample of 34 users from 60 to 83 years old and with heterogeneous previous experience with new technologies participated in the study. They performed A/B testing with a counterbalanced within-subject design. The linear navigation condition, compared to the hypertextual condition, obtained a higher success rate, lower performance time, better satisfaction ratings and greater user preference.The main contribution of this study is to demonstrate the relevance of navigation in systems oriented toward the elderly, indicating that linear navigation is more suitable for these users.     

Oppositional target domain estimation using grid-based simulation

In this paper we address the problem of estimating the target domain for search and navigation problems. We propose oppositional target domain estimation by modeling the search and navigation environment as a grid. Typically real-world applications exhibit an environment that is extremely large, dramatically diminishing the usability of intelligent agents for search and navigation. The reduction of the size of environment, hence, can help to increase the efficiency and applicability of the agents. We address this issue by modeling the environment as a grid and estimating the target domain inside the environment. The target domain is a reduced space which includes the target. The proposed technique is specifically concerned with reducing the environment using the concept of opposition. Experimental results show significant reduction of the environment size resulting in a shorter search time.