Browsing by Author "Huang, Weidong"

Now showing 1 - 10 of 10

A novel centrality-based method for visual analytics of small-world networks
(2019-10-01)
Lin, Chun-Cheng
;
Huang, Weidong
;
Liu, Wan-Yu
;
Wu, Sheng-Feng
;
工業工程與管理學系
Nowadays, the network data that we need to deal with and make sense of are becoming increasingly large and complex. Small-world networks are a type of complex networks whose underling graphs have small diameter, shorter average path length between nodes, and a high degree of clustering structures and can be found in a wide range of scientific fields, including social networks, sociology, computer science, business intelligence, and biology. However, conventional visualization algorithms for small-work networks lead to a uniform clump of nodes or are restricted to a tree structure, making the network structure difficult to identify and analyze. This work provides a new visual analytical method to improve the situation. Different from previous methods based on spanning trees, this method first generates a weighted planar sub-network based on the measurement of network centrality metrics. A force-directed algorithm based on node-edge repulsion is then applied to visualize this sub-network into a proper layout for better understanding of the data. Finally, the remaining links are placed back to maintain the original network's integrity. The experimental results show that compared to previous methods, the proposed method can be more effective in differentiating clusters and revealing relationship patterns among individual nodes and clusters in the network. Furthermore, the proposed method is applied to a data of the semiconductor wafer manufacturing industry as a case study. The work shows that this new approach allows users to gain useful insights into the data.
Aesthetic of Angular Resolution for Node-Link Diagrams: Validation and Algorithm
(2011)
Huang, Weidong
;
Huang, Maolin
;
Lin, Chun-Cheng
;
交大名義發表
;
National Chiao Tung University
When visualizing graphs into node-link diagrams, angular resolution is often used as one of the aesthetic criteria measuring the diagram quality in terms of human comprehension. However, angular resolution has not been empirically validated for its relevance to humans. In addition, although many force-directed algorithms have been proposed for automatic graph drawing, performance evaluation of these algorithms has not been conclusive due to the lack of proper methods. To shorten these gaps, this paper 1) validates the aesthetic based on human experimental data and identifies the best of angular resolution measures used in the literature; 2) introduces a force-directed algorithm, forceAR, for improving angular resolution; 3) proposes a new framework for more reliable and thorough evaluation of force-directed algorithms. Finally as a case study, our forceAR algorithm is evaluated using this framework.
Drawing Social Networks Using Area-Labeling Rectangular Cartograms
(2012-03-01)
Lin, We Dar
;
Jhong, Shun-Yu
;
Huang, Weidong
;
Lin, Chun-Cheng
;
工業工程與管理學系
People are linked together by social networks, whose complexity depends upon a lot of factors. To our understanding, most visualization interfaces for social networks have not been designed for reflecting their factors so far. As a result, this paper tries to solve such a problem by rectangular cartogram, which is a kind of geographical visualization interface using rectangles to represent regions in a map. Besides the relative position of each rectangle can reflect actual geographical related positions, one of the main features of rectangular cartograms is to use the area size or the shape of each rectangle to reflect the information of its corresponding region, e.g., the population in that region. This paper proposes a layout approach for rectangular cartograms with area labeling for social networks, in which each region has a minimum-width constraint for accommodating a text label. To satisfy the practical use for social networks, we apply a genetic algorithm to finding the minimum-width area-labeling rectangular cartogram under some constraints. By doing so, we can visualize the labeling text on each rectangle and observe the information represented by its area size or shape at the same time. Furthermore, the proposed approach is applied to visualizing the distribution of the Facebook popularity of an enterprise in Taiwan. From the cartogram, the text label on each region can be read directly and the relation among regions as well as their popularity can be visualized at the same time, so that the enterprise can improve the regions with poor popularity by the help from the regions with high popularity.
Evaluating aesthetics for user-sketched layouts of symmetric graphs
(2018-10-01)
Lin, Chun-Cheng
;
Huang, Weidong
;
Liu, Wan-Yu
;
Chen, Wen-Lin
;
工業工程與管理學系
In evaluating aesthetics of graph drawings, recent works have provided participants with an adjacency list of a graph and asked them to sketch a pleasing layout of the graph. However, this line of research has not considered aesthetics for user-sketched layouts of graphs with symmetries, which are an important property of a given graph drawing. Therefore, the work reported in this paper focuses on empirically evaluating aesthetics for user-sketched layouts of symmetric graphs. We provided participants adjacency lists of two symmetric graphs and asked them to sketch the two graphs. We analyzed whether symmetries were shown in user-sketched drawings, and further analyzed the aesthetics based on their drawing processes and drawing preferences. In addition, our experiment includes multiple stages to analyze whether the participants had the potential learning ability to draw symmetric structures of graphs. We found that in drawing symmetrical graphs, showing symmetry was likely considered more important than minimizing edge crossings, and that most participants made substantial progress in their ability to create symmetric drawings after going through the experimental stages.
Evaluating esthetics for user-sketched layouts of clustered graphs with known clustering information
(2016-12)
Lin, Chun-Cheng
;
Huang, Weidong
;
Liu, Wan-Yu
;
Tanizar, Shierly
;
Jhong, Shun-Yu
This paper aims to empirically analyze the esthetics for user-sketched layouts of clustered graphs with known clustering information. In our experiments, given not only the adjacency list of a clustered graph but also its predefined clustering information, each participant was asked to manually sketch clustered graphs "nicely" from scratch on a tablet system using a stylus. Different from previous works, the main concern in this paper is on which graph drawing esthetics people favor when sketching their own drawings of clustered graphs with known clustering information. Another concern of this paper is on the esthetics of clustered graph layouts employed by participants which include not only characteristics and structures of the final graph layouts but also the behavior of user\'s sketching process (including layout creation and adjustment). By observing all layouts and drawing processes, the drawing strategies which participants applied and the drawing esthetics are analyzed. Results show that most participants were unsurprisingly able to draw graphs with clear presence of bridge edges and clustering cohesiveness; more importantly, to distinguish clusters within the restricted-size tablet screen during the drawing process, some of the participants were still able to make each cluster with fewer edge crossings, more symmetries, and more alignment of grid in a smaller drawing area where the cluster spreads. Our results support that to alleviate user\'s complex drawing tasks, aside from the grid-based editing function suggested by the previous work, graph drawing systems should also provide the clustering information if the structure of the graph to be drawn is known.
Evaluating overall quality of graph visualizations based on aesthetics aggregation
(2016-02-10)
Huang, Weidong
;
Huang, Mao Lin
;
Lin, Chun-Cheng
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
Aesthetics are often used to measure the layout quality of graph drawings and it is commonly accepted that drawings with good layout are effective in conveying the embedded data information to end users. However, existing aesthetic criteria are useful only in judging the extents to which a drawing conforms to specific drawing rules. They have limitations in evaluating overall quality. Currently graph visualizations are mainly evaluated based on personal judgments and user studies for their overall quality. Personal judgments are not reliable while user studies can be costly to run. Therefore, there is a need for a direct measure of overall quality. In an attempt to meet this need, we propose a measurement that measures overall quality based on individual aesthetics and gives a single numerical score. We present a user study that validates this measure by demonstrating its sensibility in detecting quality changes and its capacity in predicting the performance of human graph comprehension. The implications of our proposed measure for future research are discussed. (C) 2015 Elsevier Inc. All rights reserved.
Improving multiple aesthetics produces better graph drawings
(2013-08-01)
Huang, Weidong
;
Eades, Peter
;
Hong, Seok-Hee
;
Lin, Chun-Cheng
;
工業工程與管理學系
Many automatic graph drawing algorithms implement only one or two aesthetic criteria since most aesthetics conflict with each other. Empirical research has shown that although those algorithms are based on different aesthetics, drawings produced by them have comparable effectiveness. The comparable effectiveness raises a question about the necessity of choosing one algorithm against another for drawing graphs when human performance is a main concern. In this paper, we argue that effectiveness can be improved when algorithms are designed by making compromises between aesthetics, rather than trying to satisfy one or two of them to the fullest. We therefore introduce a new algorithm: BIGANGLE. This algorithm produces drawings with multiple aesthetics being improved at the same time, compared to a classical spring algorithm. A user study comparing these two algorithms indicates that BIGANGLE induces a significantly better task performance and a lower cognitive load, therefore resulting in better graph drawings in terms of human cognitive efficiency. Our study indicates that aesthetics should not be considered separately. Improving multiple aesthetics at the same time, even to small extents, will have a better chance to make resultant drawings more effective. Although this finding is based on a study of algorithms, it also applies in general graph visualization and evaluation. (C) 2011 Elsevier Ltd. All rights reserved.
On Clustered Graph Layouts Sketched by Users Based on Predefined Clusters
(2015)
Lin, Chun-Cheng
;
Huang, Weidong
;
Liu, Wan-Yu
;
Tanizar, Shierly
;
工業工程與管理學系
The aesthetics for user-sketched layouts of clustered graphs with known clustering information is analyzed empirically. In our experiments, given the adjacency list of a clustered graph and its predefined clustering information, each participant was asked to manually sketch clustered graphs "nicely" from scratch on a tablet system using a stylus. The main feature of this work different from the previous work is to investigate if the user\'s complex task of sketching clustered graphs "nicely" can be alleviated by providing the cluster partition information. Results show that most participants can draw graphs with clear presence of bridge edges and clustering cohesiveness.
On the medication distribution system for home health care through convenience stores, lockers, and home delivery
(1970-01-01)
Suwatcharachaitiwong, Sirirat
;
Lin, Chun-Cheng
;
Huang, Weidong
;
Hung, Lun-Ping
;
交大名義發表
Medication distribution service can be delivered based on a combination of home delivery and customer pickup. That is, medications are delivered either to customers' homes directly or to the pickup facilities (e.g. lockers) close to customers' homes. In Taiwan, there are more than 11,000 convenience stores that provide a 24-h service for customers to pick up the ordered items from e-commerce, which is unique to the world. In the medication distribution system, convenience stores can provide a unique opportunity for customers to more conveniently collect medications at stores, and also can reduce the operating cost for a logistics company providing the medication delivery service. Therefore, this work proposes a medication distribution system through convenience stores, lockers, and home delivery. Under this system, this work investigates how to simultaneously determine employment of convenience store chains, the convenience store locations to be visited, locations of lockers, vehicle routes for convenience stores and lockers, and vehicle routes for customers' homes, so that the total operating cost is minimized. This work further proposes a genetic algorithm to solve the medication distribution problem. Through simulation, the experimental results show that the proposed algorithm is able to solve the problem efficiently.
Rectangular Cartogram Visualization Interface for Social Networks
(2011)
Jhong, Shun-Yu
;
Lin, Chun-Cheng
;
Liu, Wan-Yu
;
Huang, Weidong
;
工業工程與管理學系
Social networks link people together, among which a lot of factors influences their complexity. To our understanding, so far most visualization interfaces for social networks have not reflected any of their factors. Therefore, this paper tries to solve such a problem by rectangular cartograms, which is a kind of geographical visualization interface using rectnaguls to represent regions in a map. Besides the relative position of each rectangle can reflect the actual geographical related positions, one of the main feastures of rectangular cartograms is that the area size or the shape of each rectangle can reflect the information of its corresponding region, e.g., the population in that region. This paper proposes a layout approaph for rectangular cartograms with area labeling for social networks, in which each region has a minimum-width constraint for accommodating a text label. As a result, this paper applies a genetic algorithm to finding the area-labeling rectangular cartogram with minimum width under some constraints to meet the practical use in social networks. By doing so, we can visualize the labeling text on each rectangle and observe the information represented by its area size or shape at the same time. Furthermore, the proposed approach is applied to visualizing the distribution of the Facebook popularity of an enterprise in Taiwan. From the cartogram, the text label on each region can be read directly and the relation among regions as well as the popularity can be visualized, so that the enterprise can improve the regisons with poor popularity by the help from the regions with high popularity.