• Journal of the Ergonomics Society of Korea
• /
• v.32 no.2
• /
• pp.167-177
• /
• 2013

Objective: This study aims to compare the usefulness of subjective measures which are comprised of existing methods like NASA-TLX, Bedford-scale and ZEIS and newly developed method like DALI in measuring drivers' mental workload in terms of validity, sensitivity and diagnosticity. Background: Nowadays, with the development of intelligent vehicle and HMI, mental workload of driver has become more and more important. For this reason, the studies on drivers' mental workload about driving situation and the use of information technology equipment such as mobile phones and navigations were conducted intensively. However, the studies on measuring drivers' mental workload were rarely conducted. Moreover, most of studies on comparison of subjective measures were used with performance based measure. However, performance based measures can cause distraction effect with subjective measures. Method: Participants (N=19) were engaged in a driving simulation experiment in 2 driving contexts (downtown driving and highway driving context). The experiment has 2 sessions according to driving contexts. The level of difficulties by driving contexts were adjusted according to existence of intersections, traffic signs and signals, billboards and the number of doublings. Moreover, as criteria of concurrent validity and sensitivity, the EEG data were recorded before and during the sessions. Results: The results indicated that all subjective methods were correlates with EEG in high-way driving. On the contrary to this, in downtown driving, all subjective methods were not correlates with EEG. In terms of sensitivity, multi-dimensional scales (NASA-TLX, DALI) were the only ones to identify differences between high way and downtown driving. Finally, in terms of diagnosticity, DALI was the most suitable method for evaluating drivers' mental workload in driving context. Conclusion: The DALI as newly developed method dedicated to evaluate driver's mental workload was superior in terms of sensitivity and diagnosticity. However, researchers should consider the characteristics of each subjective method synthetically according to research objective by selecting the method in subjective measures. Application: The results of this study could be applied to the intelligent vehicle and next generation of HMI design to decrease mental workload of driver and for the development of new subjective method in vehicle domain.

• Journal of Preventive Medicine and Public Health
• /
• v.53 no.6
• /
• pp.397-404
• /
• 2020

Objectives: The objective of this study was to demonstrate the effects of community-based social distancing interventions after the first coronavirus disease 2019 (COVID-19) case in Turkey on the course of the pandemic and to determine the number of prevented cases. Methods: In this ecological study, the interventions implemented in response to the first COVID-19 cases in Turkey were evaluated and the effect of the interventions was demonstrated by calculating the effective reproduction number (R_t) of severe acute respiratory syndrome coro navirus 2 (SARS-CoV-2) when people complied with community-based social distancing rules. Results: Google mobility scores decreased by an average of 36.33±22.41 points (range, 2.60 to 84.80) and a median of 43.80 points (interquartile range [IQR], 24.90 to 50.25). The interventions caused the calculated R_t to decrease to 1.88 (95% confidence interval, 1.87 to 1.89). The median growth rate was 19.90% (IQR, 10.90 to 53.90). A positive correlation was found between Google mobility data and R_t (r=0.783; p<0.001). The expected number of cases if the growth rate had not changed was predicted according to Google mobility categories, and it was estimated to be 1 381 922 in total. Thus, community-based interventions were estimated to have prevented 1 299 593 people from being infected. Conclusions: Community-based social distancing interventions significantly decreased the R_t of COVID-19 by reducing human mobility, and thereby prevented many people from becoming infected. Another important result of this study is that it shows health policymakers that data on human mobility in the community obtained via mobile phones can be a guide for measures to be taken.

• The Korean Journal of Physiology and Pharmacology
• /
• v.21 no.2
• /
• pp.179-188
• /
• 2017

With the explosive increase in exposure to radiofrequency electromagnetic fields (RF-EMF) emitted by mobile phones, public concerns have grown over the last few decades with regard to the potential effects of EMF exposure on the nervous system in the brain. Many researchers have suggested that RF-EMFs can effect diverse neuronal alterations in the brain, thereby affecting neuronal functions as well as behavior. Previously, we showed that long-term exposure to 835 MHz RF-EMF induces autophagy in the mice brain. In this study, we explore whether shortterm exposure to RF-EMF leads to the autophagy pathway in the cerebral cortex and brainstem at 835 MHz with a specific absorption rate (SAR) of 4.0 W/kg for 4 weeks. Increased levels of autophagy genes and proteins such as LC3B-II and Beclin1 were demonstrated and the accumulation of autophagosomes and autolysosomes was observed in cortical neurons whereas apoptosis pathways were up-regulated in the brainstem but not in the cortex following 4 weeks of RF exposure. Taken together, the present study indicates that monthly exposure to RF-EMF induces autophagy in the cerebral cortex and suggests that autophagic degradation in cortical neurons against a stress of 835 MHz RF during 4 weeks could correspond to adaptation to the RF stress environment. However, activation of apoptosis rather than autophagy in the brainstem is suggesting the differential responses to the RF-EMF stresses in the brain system.

• Journal of rehabilitation welfare engineering & assistive technology
• /
• v.10 no.4
• /
• pp.267-272
• /
• 2016

In the era of ultra high speed information communication technology represented by Smart phone and Tablet PC, the disable and the aged people came to be in a position of so-called 'relatively weak people' in the field of information communication due to inconvenience of use and difference in information acquisition and processing ability. Thus, a survey was conducted on Smart phone accessibility items based on previous studies of the disabled with crippled disorder, brain lesions, myelopathy and muscular disabilities having more inconvenience relatively in their use of smart phone due to upper limb dysfunctions. Especially, people with upper limb dysfunctions with relatively weak grip had big inconvenience in the conditions of uses requiring actions such as grabbing and rotating the devices, and due to the characteristics of touch screen input method of Smart phone, they had big inconvenience due to a lack of a guidance for keyboard in input. As a result of questionnaires by the type of disability, it turned out that severe myelopathy causes the most inconvenience in using smart phone.

• The Korean Journal of Health Service Management
• /
• v.10 no.3
• /
• pp.223-234
• /
• 2016

Objectives : The purpose of this study was to investigate accident cases involving electronic assistive devices, to determine how these accidents can be avoided and to devise preventative instructions for the handicapped who use these devices. Methods : This study was carried out from July 20 to October 3, 2015. A consent-based survey was conducted via mail and mobile phones targeting 700 electronic assistive device users, of which questionnaires from 290 users were collected and used in the analysis. Results : Accidents involving electronic assistive devices were investigated, especially the causes of the accidents and accident prevention education, as well as the status of the electronic assistive devices. The most common accident types were collision and falling, and it was found that the victims of the accidents usually suffered severe injury to their lower limbs. Most users used electronic assistive devices every day but rarely wore a safety belt because of discomfort. There were more incidents of collision and falling for older aged handicapped users, and the injury rate to the lower limbs was highest in handicapped elderly aged 50 years or older. Conclusions : In order to prevent accidents with electronic assistive devices in the future, a or management organizations must prepare specific safety guidelines and manage these accidents.

• Transactions of the Korean hydrogen and new energy society
• /
• v.24 no.3
• /
• pp.264-274
• /
• 2013

Piping systems play an important role in gas and oil transferring system. In the piping system, there are many elements, such as valves and flow meters. In order to check their normal operating conditions, each signal from each element is displayed on the monitor in the pipe control room. By the way, there are several accidental cases in the piping system even if all signals from the local elements are judged to be normal on the monitor in the control room. Further, opposite cases often happen even the monitor shows abnormal while the local elements work normal. To overcome this abnormal functions, it is not so easy to construct the environment in which sensors detecting the working states of all elements installed in the piping system. In this paper, a new non-contact measurement technique which can calculate the elements' delicate displacements by using a PIV(particle image velocimetry) and diagnose their working states by using a neural network is proposed. The measurement system consists of a host computer, a micro system, a telescope and a high-resolution camera. As a preliminary test, the constructed measurement system was applied to measure delicate vibrations of mobile phones. For practical application, a pneumatic system was measured by the constructed system.

• Journal of Korean Society of Transportation
• /
• v.28 no.3
• /
• pp.109-117
• /
• 2010

The purpose of advanced traffic information system(ATIS) is to help drivers save time and energy in getting to their destinations by providing traffic information through variable message sign(VMS), internet, traffic broadcasting and mobile phones. ATIS does not just provide drivers with benefits in terms of time and energy, but it provides them with psychological benefit as well, i.e., the drivers can relieve their anxiety by getting provided with traffic information. In this study, the efficiency of traffic information system is evaluated and degree of satisfaction of drivers with the system is analyzed by building satisfaction models of various media of traffic information. Each medium has different factors for satisfaction and each factor has different degree of influence, but in general, the efficiency of traffic information in helping drivers choose routes and in providing drivers with peace of mind is considered to have the highest influence on satisfaction of drivers with the system.

• Journal of KIISE
• /
• v.44 no.1
• /
• pp.71-77
• /
• 2017

There has been a recent spate in the usage of mobile device equipped GPS sensors, such as smart phones. This trend enables the posting of geo-tagged messages (i.e., multimedia messages with GPS locations) on social media such as Twitter and Facebook, and the volume of such spatial data is rapidly growing. However, the relationships between the location and content of messages are not always explicitly shown in such geo-tagged messages. Thus, the need arises to reorganize search results to find the relationship between keywords and the spatial distribution of messages. We find the smallest minimum bounding rectangle (MBR) that embedding k or more points in order to find the most dense rectangle of data, and it can be usefully used in the location search system. In this paper, we suggest efficient algorithms to discover a group of 2-Dimensional spatial data with a close distance, such as MBR. The efficiency of our proposed algorithms with synthetic and real data sets is confirmed experimentally.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.15 no.4
• /
• pp.803-809
• /
• 2011

In this paper, we present a very useful method for updating digital satellite radio broadcast channel information. When a devices equipped with function to receive Digital Satellite Radio such as Home Theater, MP3 player, mobile phones, car audio system and various other types of Digital Devices, receives new Digital satellite radio (will be mentioned as XM radio onwards) broadcast channel information, only the current received XM radio broadcast channel and N number of pre/post nearby broadcast channels are scanned randomly in zigzag manner. Then the previous XM radio broadcast channel information updated with the newly received XM radio broadcast channel information. Since this method can prevent batch update for all XM radio channel, including some channels which less likely did not select by user, update process for real time frequently changed XM radio broadcast channel information can be performed efficiently with minimal or without delay.

• The KIPS Transactions:PartA
• /
• v.14A no.5
• /
• pp.279-286
• /
• 2007

The need of contents adaptation in ubiquitous environments is growing to support multiple target platforms for 3D graphics contents. Since 3D graphics deal with a large data set md a high performance, a service adaptation for context changing is required to manipulate graphics contents with a more complicated method in multiple devices such as desktops, laptops, PDAs, mobile phones, etc. In this paper, we suggest a new notion of service adaptation middleware based on service rendering algorithm, which provides a flexible and customized service for user-centric 3D graphics contents. The service adaptation middleware consists of Service Adaptation(SA) for analyzing environments and Service Rendering(SR) for reconfiguring customized services by processing customized data. These adaptation services are able to intelligently and dynamically support the same computer graphics contents with good quality, when user environments are changed.