kichol lee - Academia.edu (original) (raw)

Papers by kichol lee

Auditory situation awareness (ASA) is essential for safety and survivability in military operatio... more Auditory situation awareness (ASA) is essential for safety and survivability in military operations where many of the hazards are not immediately visible. Unfortunately, the Hearing Protection Devices (HPDs) required to operate in these environments can impede auditory localization performance. Promisingly, recent studies have exhibited the plasticity of the human auditory system by demonstrating that training can improve auditory localization ability while wearing HPDs, including military Tactical Communications and Protective Systems (TCAPS). As a result, the U.S. military identified the need for a portable system capable of imparting auditory localization acquisition skills at similar levels to those demonstrated in laboratory environments. The purpose of this investigation was to design and develop a Portable Auditory Situation Awareness Training (PASAT) system capable of reproducing acoustically accurate localization cues similar to a proven laboratory grade system. Extensive r...

: The Virginia Tech Auditory Systems Laboratory (ASL) research effort for the DoD Hearing Center ... more : The Virginia Tech Auditory Systems Laboratory (ASL) research effort for the DoD Hearing Center of Excellence was aimed at the development of an efficient, in- laboratory implementable test battery for auditory situation awareness (ASA) that objectively quantified the ASA performance afforded by various Tactical Communications and Protection Systems (hereafter, TCAPS) and augmented/advanced Hearing Protection Devices (hereafter, HPDs) used by the U.S. military. Specifically, each of the fundamental ASA task elements of Detection, Recognition/Identification, Localization, and COMmunications, hereafter termed DRILCOM ASA elements, is measured in the psychophysical test battery that was the primary deliverable from the research. The individual ASA elements scores from the test battery were kept separate so that performance on each element of ASA could be ascertained, and via statistical analysis, the individual elements sets of scores were applied to determine the DRILCOM test battery...

International Journal of Audiology, 2019

Objective: Design an optimised auditory azimuth localisation training protocol by: (1) differing ... more Objective: Design an optimised auditory azimuth localisation training protocol by: (1) differing the number of training stimuli presentations to determine the highest angular accuracy achieved in the fewest training sessions, (2) evaluating the presence of training transfer from a broadband stimulus to untrained militaryrelevant stimuli and (3) measuring the effect of differing training strategies on localisation accuracy. Design: Two pilot studies of 18 and six subjects, respectively, determined the number of presentations and type of stimuli to be included in a localisation training experiment that evaluated different training strategies. In the pilot studies, participants trained using eight Learning Units (LU) and then tested using untrained stimuli. In the main experiment, 40 participants completed eight LUs using four different learning strategies, with 10 participants randomly assigned to each condition. Sample: All participants were ages 18-42 normal-hearing listeners with thresholds not exceeding 25 dB HL and asymmetry not exceeding 15 dB HL. Results: Transfer of training occurred using three of the four untrained stimuli. The training strategy that resulted in the highest localisation accuracy involved active participation. Conclusions: Training with a broadband stimulus transfers to untrained broadband stimuli. Training involving the active participation strategy resulted in the greatest localisation accuracy.

International Journal of Audiology, 2018

(1) determine if untrained, normal-hearing listeners could learn, with regimented practice trials... more (1) determine if untrained, normal-hearing listeners could learn, with regimented practice trials, to localise a dissonant tonal complex while wearing electronic hearing protectors and achieve equivalent performance to the unoccluded ear, (2) determine if different protector designs affect the localisation learning curve, and (3) determine if a sequential training regimen could be used to determine whether a device is not amenable to training effects. All subjects completed paired training and testing trials, in 12 Learning Units (LU), first with the open ear., then half with device A, a US Army TCAPS (INVISIO V R X50), and the other half with device B (a prototype). Both groups then finished with the opposite device. Ten subjects participated, with thresholds below 25 dBHL, bilateral symmetry below 15 dBHL, and naivety with electronic protectors and localisation testing. Subjects eventually approached their open ear capability with device A, but never reached equivalent open ear nor asymptotic performance with device B. Depending upon a protector's sound transduction, frequency response, and other characteristics, different amounts of training are required to adapt. The training protocol has value in determining device acceptability based on the training burden required, especially when mission-related localisation performance is important.

The Journal of the Acoustical Society of America, 2016

An objective, computer-controlled test battery was developed for measuring the effects of hearing... more An objective, computer-controlled test battery was developed for measuring the effects of hearing protection devices (HPDs) and TCAPS, on auditory situational awareness (ASA). Four independent ASA tasks with military relevance were tested: Detection-Recognition/Identification-Localization-Communication (DRILCOM). Detection employed threshold-shift with seven 1/3-octave bands, an AK-47 burst, and rifle cocking. Detection signals emanated from in front of the subject (0 degrees), or at 90, 180, or 270 degrees, to evaluate directionality. The Recognition/Identification task employed 36 signals combined in triads, wherein one “target” sound from 0 or 90 degrees had to be identified, at S/N ratios of -10, 0, and + 10. Localization employed a dissonant pure tone chord, spanning 104-7880 Hz, which provided interaural time and interaural level cuing. Localization entailed 360-degrees of azimuth in 30-degree increments, and 30-degrees in frontal elevation, at a S/N of + 10. The Communications task, addressing pass...

International journal of audiology, 2016

To investigate the effect of controlled low-speed wind-noise on the auditory situation awareness ... more To investigate the effect of controlled low-speed wind-noise on the auditory situation awareness performance afforded by military hearing protection/enhancement devices (HPED) and tactical communication and protective systems (TCAPS). Recognition/identification and pass-through communications tasks were separately conducted under three wind conditions (0, 5, and 10 mph). Subjects wore two in-ear-type TCAPS, one earmuff-type TCAPS, a Combat Arms Earplug in its 'open' or pass-through setting, and an EB-15LE™ electronic earplug. Devices with electronic gain systems were tested under two gain settings: 'unity' and 'max'. Testing without any device (open ear) was conducted as a control. Ten subjects were recruited from the student population at Virginia Tech. Audiometric requirements were 25 dBHL or better at 500, 1000, 2000, 4000, and 8000 Hz in both ears. Performance on the interaction of communication task-by-device was significantly different only in 0 mph win...

International Journal of Audiology, 2016

Objective: To design a test battery and conduct a proof-of-concept experiment of a test method th... more Objective: To design a test battery and conduct a proof-of-concept experiment of a test method that can be used to measure the detection performance afforded by military advanced hearing protection devices (HPDs) and tactical communication and protective systems (TCAPS). Design: The detection test was conducted with each of the four loudspeakers located at front, right, rear and left of the participant. Participants wore 2 in-ear-type TCAPS, 1 earmuff-type TCAPS, a passive Combat Arms Earplug in its ''open'' or pass-through setting and an EB-15LEÔ electronic earplug. Devices with electronic gain systems were tested under two gain settings: ''unity'' and ''max''. Testing without any device (open ear) was conducted as a control. Study sample: Ten participants with audiometric requirements of 25 dBHL or better at 500, 1000, 2000, 4000, 8000 Hz in both ears. Results: Detection task performance varied with different signals and speaker locations. The test identified performance differences among certain TCAPS and protectors, and the open ear. Conclusions: A computer-controlled detection subtest of the Detection-Recognition/Identification-Localisation-Communication (DRILCOM) test battery was designed and implemented. Tested in a proof-of-concept experiment, it showed statistically-significant sensitivity to device differences in detection effects with the small sample of participants (10). This result has important implications for selection and deployment of TCAPS and HPDs on soldiers and workers in dynamic situations.

Publikationsansicht. 31416631. Reduced order model for two-phase flows / (2003). Lee, Kichol. Abs... more Publikationsansicht. 31416631. Reduced order model for two-phase flows / (2003). Lee, Kichol. Abstract. Thesis (MS)--San Diego State University, 2003.. Includes bibliographical references (leaves 31-32). Details der Publikation. Download, http://worldcat.org/oclc/53034247. ...

… of NeuroEngineering and …, Jan 1, 2011

Loss of postural stability can increase the likelihood of slips and falls in workplaces. The pres... more Loss of postural stability can increase the likelihood of slips and falls in workplaces. The present study intended to extend understanding of the effects of frequency and pressure level of sound on postural stability during standing. Eleven male subjects participated. Standing on a force platform, the subjects' center of pressures were measured under different combinations of pressure level and frequency of the sound. Variables such as the position variability of COP and the length of postural sway path in anterior-posterior (AP) and medio-lateral (ML) direction were evaluated. Subjective ratings of perceived disturbance at each experimental condition were also obtained using a 7-point rating scale. Results showed that the length of sway path and the position variability of COP increased as the frequency of sound increased in posterior-anterior axis. The effect of sound pressure level, however, was not significant on both the postural sway length and the position variability of COP. These results suggested substantial disturbance of standing balance system among subjects exposed to high frequency noise. The results implied that physical workers should be alerted that their abilities of postural balance could be degraded significantly as disturbance caused by a sound existed.

AIP Conference Proceedings, Jan 1, 2003

Numerical simulations of transport phenomena in fluidized beds are carried out to investigate the... more Numerical simulations of transport phenomena in fluidized beds are carried out to investigate the complex interaction between gas and solid particles, and to explore the validity of a reduced order model based on the Proper Orthogonal Decomposition. The ...

Proceedings of the Human Factors and …, Jan 1, 2011

Abstract Previous research has shown that auditory occlusion effects could inhibit people from us... more Abstract Previous research has shown that auditory occlusion effects could inhibit people from using hearing protection devices or hearing aids, which raises safety and usability concerns. The objective of this study was to evaluate occlusion effects as a function of ...

key words: occlusion effect, hearing aid, balloon plug ii

PLoS Pathogens, Jan 1, 2007

The possibility of using computer simulation and mathematical modeling to gain insight into biolo... more The possibility of using computer simulation and mathematical modeling to gain insight into biological and other complex systems is receiving increased attention. However, it is as yet unclear to what extent these techniques will provide useful biological insights or even what the best approach is. Epstein-Barr virus (EBV) provides a good candidate to address these issues. It persistently infects most humans and is associated with several important diseases. In addition, a detailed biological model has been developed that provides an intricate understanding of EBV infection in the naturally infected human host and accounts for most of the virus' diverse and peculiar properties. We have developed an agent-based computer model/simulation (PathSim, Pathogen Simulation) of this biological model. The simulation is performed on a virtual grid that represents the anatomy of the tonsils of the nasopharyngeal cavity (Waldeyer ring) and the peripheral circulation-the sites of EBV infection and persistence. The simulation is presented via a user friendly visual interface and reproduces quantitative and qualitative aspects of acute and persistent EBV infection. The simulation also had predictive power in validation experiments involving certain aspects of viral infection dynamics. Moreover, it allows us to identify switch points in the infection process that direct the disease course towards the end points of persistence, clearance, or death. Lastly, we were able to identify parameter sets that reproduced aspects of EBV-associated diseases. These investigations indicate that such simulations, combined with laboratory and clinical studies and animal models, will provide a powerful approach to investigating and controlling EBV infection, including the design of targeted anti-viral therapies.