브롬이온존재하에서 플라즈마에 의한 암모니아의 탈질에 관한 연구

권지영,임익현,정팔진 全北大學校 附設 都市및環境硏究所 2000 都市 및 環境硏究 Vol.15 No.1

This study was the basic experiment of direct denitrification of NH_3-N. The synthetic wastewater(10㎎/L as NH_3-N) in presence of bromide ion was treated by plasma. The results as follows ; When bromide ion was not present in the wastewater, nitrification or denitrification did not occur. Denitrification of ammonia by plasma in presence of bromide ion was increased in proportion to bromide ion.

익산천의 수질변동 특성과 수질오염 요인분석에 관한 연구

정팔진,임익현,김민정,권지영 全北大學校 附設 都市및環境硏究所 1999 都市 및 環境硏究 Vol.14 No.1

In this study, Variation Characteristics and Analysis of Water Pollution Factors in Iksan stream were investigated and samples were collected 7 times during this study period at nine points. The water quality criteria of Iksan stream is first grade but it is over fifth grade because of domestic wastewater and livestock wastewater. Particularly, livestock wastewater from Wang-kung affect water quality of Iksan stream. So livestock wastewater should be controlled to recover water quality of Iksan stream.

A Study on the Effect of Pre-cue in Simple Reactions on Control-on-Display Interfaces

Ji Hyoun Lim,Junyoung Choi,Youngsu Kim 대한인간공학회 2011 大韓人間工學會誌 Vol.30 No.4

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.

Comparing Elder Users' Interaction Behavior to the Younger

Ji Hyoun Lim,Taebeum Ryu 대한인간공학회 2012 大韓人間工學會誌 Vol.31 No.2

Objective: This study presents an observation and analysis on behavioral characteristics of old users in comparison to young users in the use of control on display interface. Background: Touch interface which allows users to control directly on display, is conceived as delight and easy way of human-computer interaction. Due to the advantage in stimulus-response ensemble, the old users, who typically experiencing difficulties in interacting with computer, would expected to have better experience in using computing machines. Method: Twenty nine participants who are over 50 years old and 14 participants who are in 20s years old were participated in this study. Three primary tasks in touch interface, which are tap, move, and flick, were delivered by the users. For the tap task, response time and point of touch response were collected and the response bias was calculated for each trial. For the move task, delivery time and the distance of finger movements were recorded for each trial. For the flick task, task completion time and flicking distance were recorded. Results: From the collected behavioral data, temporal and spatial differences between young and old users behavior were analyzed. The older users showed difficulty in completing move task requiring eye-hand coordination.

Evaluation of Classification Models for Goals in Visual Search Using Driver Segments Based on Cognitive Characteristics

Ji Hoon Kim,Ji Hyoun Lim 대한인간공학회 2014 대한인간공학회 학술대회논문집 Vol.2014 No.5

Drivers continuously shift their visual attention between the road and the dashboard to search information which they need for driving. According to Cooper (2013), their driving performance is affected by cognitive aspects; therefore, it is necessary to consider drivers’ cognitive characteristics and abilities in a driving context. Existing studies on the evaluation of drivers’ performance are focused on gender or age difference (Oltedal, 2006; Lonczak, 2007). In the precedent study (Jo & Lim, 2013), 114 users were clustered into eight segments, and for three selected segments, nine users were recruited for eye movement data gathering during a dual task of driving and visual search. In this study, logistic regression classification models for each segment were developed based on the eye movement data. The models for the segment based on a driver’s cognitive characteristics showed higher accuracies than the models for the male and female groups. This could be a preliminary study introducing the importance of using drivers’ cognitive characteristics in designing visual information for vehicles.

Study on Implicit Associations between Gestures and Commands

Ji Hyoun Lim,Chun Ik Jo,Junho Kim 대한인간공학회 2012 대한인간공학회 학술대회논문집 Vol.2012 No.5

Objective: This study presents a method to investigate implicit associations between gestures and commands when people use gestures to control a device. Background: Selecting motions for gesture interaction is critical for its usability. The design of motion is, however, limited by the technology utilized in motion recognition system. Therefore, proposing a gesture considering technology limitation is necessary. Method: Thirty nine gestures for the depth camera recognition system were listed, and 30 commands for smart TV control were identified. For each gesture, 30 participants rated top three commands which would match up with the given gesture. Results: Agreement scores were calculated for each gesture, and the association between the gesture element and the command element were calculated. Conclusion: Complex gestures showed low agreement scores, and the association matrix was calculated. Application: This study could be applied to any device considered to adopt gesture interaction for device control.

Cognitive Architectures for Computational Cognitive Modeling in Ergonomic Practice

Ji Hyoun Lim(임지현) 대한인간공학회 2007 대한인간공학회 학술대회논문집 Vol.- No.-

Behavioral Difference between Young and Old Users in Control on Display Interface

Ji Hyoun Lim,Ochae Kwon,Jae-hyun Choi 대한인간공학회 2011 대한인간공학회 학술대회논문집 Vol.2011 No.10

This paper presents an experimental study on behavioral characteristics of old users in the comparison to young users in the use of control on display interface. Twenty-nine participants who are over 50 years old and 14 participants who are in 20s years old were participated in this study. Three primary tasks in touch interface, which are tap, move, and flick, were given in the order. For the tap task, delivery time and point of touch response were collected and the response bias was calculated for each trial. For the move task, delivery time and the distance of finger movements were recorded for each trail. For the flick task, delivery time and flicking distance were recorded. Form the collected behavioral data, temporal and spatial differences between young and old users were analyzed. The older users showed difficulty in completing move task, and for the task required visual information processing for given target icon, tap and move, the older user took longer time to complete each trial.

A Study on the Cognitive Model of Users Engaged in Simple Reactions of Control-on-Display Interfaces

Ji Hyoun Lim,Junyoung Choi,Youngsu Kim 대한인간공학회 2011 대한인간공학회 학술대회논문집 Vol.2011 No.5

Objective: This study focuses on the factors of visual stimulus affecting finger movement response in the context of control-on-display interfaces. Background: A conceptual cognitive model was postulated to identify the relevant factors and hypothesize their effects, leading to the experimental design. The design aimed to reveal the effects induced by (1) existence of precue, (2) location of the center-of-gravity, and (3) contrast ratio between target and background. 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: Given a precue, response time was reduced but with accuracy penalized. When given different shapes of visual stimuli, participants' responses were biased toward the target's center of gravity. Targets with brighter contrast compared to the background induced increased response time and reduced accuracy. Conclusion: This study showed variations in the physical and psychophysical aspects of visual stimuli which influence finger responses. Graphic User Interfaces (GUI) on control-on-display interfaces should therefore be designed considering not only visibility but also controllability. 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.

Eye Movement Model based on Reinforcement Learning

Ji Hyoun Lim 대한인간공학회 2011 대한인간공학회 학술대회논문집 Vol.2011 No.5