• Journal of the Ergonomics Society of Korea
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• v.29 no.5
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• pp.763-770
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• 2010

The use of web widgets on desktop and mobile devices has been increasing rapidly. Web widgets provide access to activities and information from various sources across the web. As the number of supported widgets increases, managing widgets and finding relevant or interesting widgets becomes more complex. In addition, interacting with widgets in web service systems can be difficult, especially for novice users. Up to this point, there has been little research on web widget usability. This paper performs an experimental study regarding user interfaces of web widgets based on the mouse tracking and work-flow analysis. In the experiment, four sites providing widget services are chosen - iGoogle, Netvibes, My yahoo, and Wizard. The experiment participants perform three assigned tasks in the chosen sites, and their mouse operations are recorded using Camtasia, a screen casting software. Mouse tracking analysis is performed based on the recorded data in order to analyze common user behaviors. In addition, work-flow diagrams representing the operational flows to carry out the given tasks in each web site are constructed so as to visually and systematically analyze detailed usage patterns. The experimental study results presented in this paper can contribute to developing guidelines for highly usable and accessible interface design of web widgets.

• Journal of the Ergonomics Society of Korea
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• v.30 no.4
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• pp.563-569
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• 2011

Objective: This study focuses on the effects of pre-cues informing the location of upcoming visual stimulus on finger movement response in the context of control-on-display interfaces. Background: Previous research on pre-cues focus on attention allocation and motion studies were limited to indirect control conditions. The design of this study aimed to collect data on the exact landing point for finger-tap responses to a given visual stimulus. Method: Controlled visual stimuli and tasks were presented on a UI evaluation system built using mobile web standards; response accuracy and response time were measured and collected as appropriate. Among the 16 recruited participants, 11 completed the experiment. Results: Providing pre-cue on the location of stimulus affected response time and response accuracy. The response bias, which is a distance from the center of stimulus to the finger-tap location, was larger when the pre-cue was given during a one-handed operation. Conclusion: Given a pre-cue, response time decreases, but with accuracy penalized. Application: In designing touch-screen UI's - more strictly, visual components also acting as controllers - designers would do well to balance human perceptual and cognitive characteristics strategically.

• Journal of Biosystems Engineering
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• v.33 no.3
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• pp.157-166
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• 2008

Protected horticulture is labor-intensive. It necessitates great amount of labor in many tasks including grafting, pollination and harvesting. Particularly, carrying crops involves the most intensive labor which leads to a high risk of musculoskeletal disorder. Thus, this study aims at developing an ergonomic vehicle to reduce this intensity of labor and ergonomic evaluation by applying the newly developed vehicles to REBA. 5 healthy male subjects with no records of any musculoskeletal disorder were participated in this study. The experimental units were divided into three categories: lifting, lowering and pushing tasks. The results showed that the developed vehicle received less loads in group B (arms and wrists) than in group A (trunk, neck and legs). Especially, the developed vehicle scored $1.0{\sim}4.4$ in group C on REBA while the conventional wheelbarrow got $3.0{\sim}7.6$, regardless of working postures. In conclusion, the developed ergonomic vehicle provided less loads for human bodies compared to the conventional one.

• Journal of the Ergonomics Society of Korea
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• v.22 no.3
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• pp.57-73
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• 2003

Although body pressure distribution is sensitive to movements and is relatively simple to measure even in small space, there are few researches involving applications to driver's posture and its change. The main objective in this study is the application of body pressure distribution measurements for the prediction of the driver's posture and its change. This requires quantitative analyses of the dynamic body pressure distribution, which is the change of body pressure distribution with time. The experiment involved 16 male subjects who drove for 45 minutes in a seating buck. Measurement time, stature group, and lumbar support prominence were selected as independent variables, with subjective ratings of driver's discomfort, body posture data of hip, torso. knee angle, and body pressure data variables as dependent variables. The body pressure change variables and subjective ratings were found to increase as the measurement time increased and body pressure ratio variables reflected the torso angle. From the results and analysis of the body posture data and subjective rating results, it was predicted that the seats and the design of the lumbar supports used in the experiment was not fit for tall subjects, which could also be confirmed through the body pressure distribution data.

• Journal of the Ergonomics Society of Korea
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• v.15 no.2
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• pp.71-88
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• 1996

For understanding skin temperature based on clothing design from a viewpoint of comfortable wearing, the skin temperature, physiological reactions(body temperature, blood pressure and pulse) and physilolgical response(thermal sensation, comfort sensation and perceptive sweaty sensation) were measured on condition tha t5 naked healthy male exposed to serveral environmental temperatures,( $20{\pm}1.0^{\circ}C$ ,$28{\pm}1.0^{\circ}C$ and $32{\pm}1.0^{\circ}C$). As the results of this testing, the regional skin temperature was varied for 90min just after expose to those the environment but was generally stabilized for the nest 90min. It was proved the difference of the regional skin temperature at low temperature environmental($20{\pm}1.0^{\circ}C$) was larger than at high temperature environmental($32{\pm}1.0^{\circ}C$) and inder serveral environmental temperature,the degree of the regional skin was not equal. Except in case of the thigh, the front of all regional skin temperature turned out higher than the back of them. According to change of environmental temperature, body temperature and pulse were altered. In the pshycological response, 'thermal sensation-comfort sensation' was felt to 'slightly warm - comfortable' at $28{\pm}1.0^{\circ}C$of the environmental temperature, and 'perceptive sweaty sensation', wneh it was said 'sweat' at only $32{\pm}1.0^{\circ}C$ of it.

• Journal of the Ergonomics Society of Korea
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• v.34 no.3
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• pp.235-245
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• 2015

Objective: The purpose of this study is to develop visual complexity metrics based on theoretical bases. Background: With the development of IT technologies, drivers process a large amount of information caused by automotive human-machine interface (HMI), such as a cluster, a head-up display, and a center-fascia. In other words, these systems are becoming more complex and dynamic than traditional driving systems. Especially, these changes can lead to the increase of visual demands. Thus, a concept and tool is required to evaluate the complicated systems. Method: We reviewed prior studies in order to analyze the visual complexity. Based on complexity studies and human perceptual characteristics, the dimensions characterizing the visual complexity were determined and defined. Results: Based on a framework and complexity dimensions, a set of metrics for quantifying the visual complexity was developed. Conclusion: We suggest metrics in terms of perceived visual complexity that can evaluate the in-vehicle displays. Application: This study can provide the theoretical bases in order to evaluate complicated systems. In addition, it can quantitatively measure the visual complexity of In-vehicle information system and be helpful to design in terms of preventing risks, such as human error and distraction.

• Journal of the Ergonomics Society of Korea
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• v.9 no.2
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• pp.29-35
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• 1990

To investigate and analyze of the human brain-wave changes during 3-dimenslonal image load were expected to take not only an important basic information of 3-dimensional TV usage but also 3-dimensional image design. In this experiment, to analyze the difference of visual analyze handing system for which we present the 2- dimensional image having no parallex and 3-dimensional image by visual evoked potentials(VEP). 2-dimensional image and 3-dimensional image displayed on the screen through video. In the test, the time interval was one sec for presentation of stimulus considering united time of visual information of right eye and left eye during watching the 3-dimensional image also display time interval was 200 mesc for each stimulus image. Results are as follow, (1) N190 appears faster 16msec-20msec in the point of Fz, Cz, Pz, Oz when loaded 3D4 angle than 2D3 angle. (2) About of the P300, 3D4 angle(Otherwise, Oz point was reverse) and in the case of no equipment of liquid crystal shutter, there appeared PEAK near the P250. (3) There were 5% significant difference when the liquid crystal shutter was equiped and didn't, Therefore, this phenomenon show the possibility that Liquid crystal shutter influences on Visual Evoked Potentials.

• Journal of the Ergonomics Society of Korea
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• v.17 no.1
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• pp.115-123
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• 1998

We study the ski wear which are compared at the materials and the designes and their human physiological and phychological response during exercise in a cold and air-conditioned enviroments. Five men exercises in the experiment room with four types of ski-wears : two of one-piece and two of two-piece : two of special material and two of a normal material, respectively. We keep the environment at $-5^{\circ}C$ and speed of 3.6 mile/hr during the measurement of 13 points, which is a mean model of the Muju ski-resort at January 1996. We conclude the followings : 1. The ski-wear with special materials have higher than the normal type at mean skin temperature and rectal temperature. 2. Changes of temperature withing the clothes during the exercise is small, but the humidity within the clothes abruptly increases because of the weight loss. 3. Type A ski-wear with the special material has $295.5g/m^2hr$ weight loss, which is higher, and type D ski-wear is smaller 4. The special material shows comfortable in the thermal sensation. 5. In the design aspect of the ski-wears, the two-piece type ski-wear shows higher skin temperature and temperature & humidity within the clothes than the one-piece type due to the effect of the multiplicity.

• Journal of the Ergonomics Society of Korea
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• v.17 no.3
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• pp.61-70
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• 1998

The purpose of this paper is to evaluate the input methods of the numeric keypads that are widely used in various types of consumer and industrial electronic products. Three methods to enter numerals using keypads were compared: (1) Machine Intelligence, (2) + 100 key, and (3) Enter key input methods. Experiments were conducted to compare these three input methods for the channel selection of TV. Experimental prototypes which simulate TV user interfaces were developed using $RAPID^{TM}$ for usability testings. In the experiment, data on subject performance such as completion time, operational errors, and user interaction were collected through auto-logging method and video recording. After each test session, subjective preference was also asked using a questionnaire. In order to analyze the type of operation errors and the error causation, operation sequences were analyzed from the collected data. The Enter key input method showed better performance than other input methods. Based on these results. we can conclude that the input method using numeric keypads should be compatible with generic number counting(to input ch 7, it would be better to input 7 directly than to input 07 or 007) and should switch the channel as quickly as possible. This conclusion can be applied to the design of user interfaces which require numeral inputs.

• Journal of the Ergonomics Society of Korea
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• v.33 no.5
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• pp.355-363
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• 2014

Objective:The purpose of this study is to design a three-set type (Sebulsik) keyboard that is to input Korean text with no shifted keys and also compatible with the standard Korean computer keyboard or ANSI keyboard. Background: The KS computer keyboard is two-set type (Dubulsik). Existing and proposed designs of three-set type of past studies are not compatible with KS or ANSI keyboard and are complex with many redundant letters. Method: The number of Korean letters for 3-set type is analyzed. Then Korean letters are arranged with normality and with spatial compatibility to the KS Korean keyboard, and symbols were arranged to same positions with ANSI keyboard. Results: Initial consonants of 14 numbers and 6 vowels are arranged as exactly same positions of KS keyboard, and other vowels are arranged with spatial compatibility. Symbols are arranged to the same positions with ANSI keyboard, and 10 digits are confirmed and has compatibility to International standard. Conclusion: A 38-key model, 38K, is designed to require minimal keys to input Korean text with no shifted keys, increased the compatibility to the KS Korean computer keyboard. Application: Using the proposed 38-key model, 38K, it can be taken into account for keyboards in industrial production. It is applicable to user group of 3-set type Korean keyboard with more easy than past keyboards.