• IEMEK Journal of Embedded Systems and Applications
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• v.17 no.5
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• pp.281-288
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• 2022

According to statistics conducted by the Korea Coast Guard, the number of accidents on small boats under 5 tons is increasing every year. This is because only a small number of people are on board. The previously developed maritime distress and safety systems are not well distributed because passengers must be equipped with additional remote equipment. The purpose of this study is to develop a distress awareness system that recognizes man over-board situations in real time. This study aims to present the part of the passenger tracking system among the small ship's distress awareness situational system that can generate passenger's location information in real time using deep learning based object detection and tracking technologies. The system consisted of the following steps. 1) the passenger location information is generated in the form of Bounding box using its detection model (YOLOv3). 2) Based on the Bounding box data, Deep SORT predicts the Bounding box's position in the next frame of the image with Kalman filter. 3) When the actual Bounding Box is created within the range predicted by Kalman-filter, Deep SORT repeats the process of recognizing it as the same object. 4) If the Bounding box deviates the ship's area or an error occurs in the number of tracking occupant, the system is decided the distress situation and issues an alert. This study is expected to complement the problems of existing technologies and ensure the safety of individuals aboard small boats.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.9
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• pp.138-144
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• 2012

In this paper, we introduce the time-domain equalizer in orthogonal frequency division multiplexing (OFDM) systems using orthogonal matching pursuit (OMP) algorithm. Since OFDM system inserts guard intervals, it shows robust performance against multi-path fading. However, in Doppler channel, inter-carrier interference (ICI) occurs because an orthogonality of sub-carriers does not maintain. A least squares (LS) algorithm is common method of time-domain equalizer, but if a channel length is longer, the performance deteriorates by noise. The multi-path fading is a summation of the different delay signal. And that has sparse properties in time-domain. Because the OMP algorithm of the compressive sensing (CS) algorithm restores the channel by choosing the important elements of sparse channel, it can reduce the influence of noise. We simulate the performance of time-domain equalizer in OFDM system with various channel environments using OMP algorithm compared with other equalization method.

• Journal of Environmental Health Sciences
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• v.43 no.4
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• pp.267-272
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• 2017

Objectives: The purposes of the study were to analyze the temporal variation of carbon dioxide ($CO_2$) and particulate matter (PM) in daycare centers and evaluate the appropriateness of the official test method of one-time measurement. Methods: Indoor air quality in 46 daycare centers in the Seoul Metropolitan Area was measured as specified in the official test method of Indoor Air Quality Management law. In addition, indoor air quality in the 46 daycare centers was measured over 37 days using a real-time monitor (AirGuard K). Results: The daily means of $CO_2$ and PM in the 46 daycare centers were $1042.74{\pm}134.45ppm$ and $67.60{\pm}18.25{\mu}g/m^3$, respectively. Indoor air quality in the daycare centers showed significant temporal fluctuation. Measurements for single days were significantly different from the 37-day average exposure. Relative error of short term exposure decreased with an increase in the number of sampling days. The noncompliance rate for $CO_2$ using the official testing method was 2.17%, and none exceeded the $PM_{10}$ standard of $100{\mu}g/m^3$. With monitoring over 37 days, the daily noncompliance rate for $CO_2$ was 50.4% and the daily noncompliance rate for PM was 13.8%. Conclusions: When the official test method evaluates the indoor air at daycare centers one day per year, the results may not represent actual indoor air quality over a longer period of time. Real-time monitoring devices could be an alternative for managing indoor air quality.

• Journal of National Security and Military Science
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• s.7
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• pp.271-303
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• 2009

"Ubiquitous sensor network" definition is this-Someone attaches electro-magnetic tag everything which needs communication between man to man, man to material and material to material(Ubiquitous). By using attached every electro-magnetic tag, someone detects it's native information as well as environmental information such as temperature, humidity, pollution and infiltration information(Sensor). someone connects it realtime network and manage generated information(Network). 21st century's war is joint combined operation connecting with ground, sea and air smoothly in digitalized war field, and is systematic war provided realtime information from sensor to shooter. So, it needs dramatic development on watch reconnaissance, command and control, pinpoint strike etc. Ubiquitous computing and network technologies are essential in national defense to operate 21st century style war. It is possible to use many parts such as USN combined smart dust and sensor network to protect friend unit as well as to watch enemy's deep area by unmanned reconnaissance, wearable computer upgrading soldier's operational ability and combat power dramatically, RFID which can be used material management as well as on time support. Especially, unmanned watch system using USN is core part to transit network centric military service and to get national defense efficiency which overcome the dilemma of national defense person resource reducing, and upgrade guard quality level, and improve combat power by normalizing guardian's bio rhythm. According to the test result of sensor network unmanned watch system, it needs more effort and time to stabilize because of low USN technology maturity and using maturity. In the future, USN unmanned watch system project must be decided the application scope such as application area and starting point by evaluating technology maturity and using maturity. And when you decide application scope, you must consider not only short period goal as cost reduction, soldier decrease and guard power upgrade but also long period goal as advanced defense ability strength. You must build basic infra in advance such as light cable network, frequency allocation and power facility etc. First of all, it must get budget guarantee and driving force for USN unmanned watch system project related to defense policy. You must forwarded the USN project assuming posses of operation skill as procedure, system, standard, training in advance. Operational skill posses is come from step by step application strategy such as test phase, introduction phase, spread phase, stabilization phase and also repeated test application taking example project.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.10
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• pp.7176-7181
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• 2015

This thesis is about the system where the solar module is attached to the high functional guardrail posts with anti-weed, anti-plant, and road-kill applied to produce internal power, enabling the integrated control and real-time monitoring of appearance of wildlife and road conditions using the USN. The whole system consists of a photovoltaic module(PV), a detection sensor(pyroelectric), a controller(operation select and motion sensor), the USN system, the DB(sound and flash), an output unit of sound and flash, and the control system of road-kill prevention and safety induction for vehicles. Thus this study aims to address the remote control and monitoring system of multipurpose guardrails to improve road environment, prevent road-kills, protect wild animals, and guide cars safely by using the USN which is combined with new renewable energy and IT convergence technology. As a result of the study on the remote control and monitoring system using the USN, it was ascertained that the response time of the unmanned sensing system was within 5.1 ms with the current consumption of 0.328 mA, and the data transmission speed of the remote control system was 250 kbps with the current consumption of 0.283 mA.

• Korean Security Journal
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• no.33
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• pp.103-135
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• 2012

The object is that this research searches the relationship of the office given condition actual condition of the country important facility private security guard and job satisfaction degree. In order to grasp and analyze the real state of the country important facility private security guards directly, the questionnaire, that is the general measurement tool, was utilized and the guard whom it works in the airport, the port region and general work place, that is the national important facility of Busan and Ulsan area, was aimed at. The enough survey object was illustrated to the facility and person in charge in the security company and the item was previewed and the total 400 sheets was distributed and 331 sheets (82.8%) except the doubleness subject intention and incongruent questionnaire was utilized for the analysis. The statistic processing of collected data utilized the SPSS version 15.0 the statistical package program through data coding and cleaning process and performed the frequency analysis, reliability analysis, t-test, one way analysis of variance, Pearson analysis, and regression analysis. The relationship of the office given condition actual condition of the guard about the national important facility and job satisfaction degree was classified into the interpersonal relationship, task characteristic, office environment, and complement factor and the difference of the job satisfaction degree according to the general characteristic was verified. If the conclusion obtained through the method of study described in the above looked at, for as to general tendency, the low wages and poor field environment was continued. In the general characteristic, the man was higher than the excitation about the job satisfaction level. As there was lots of the age and the scholarship was low, the age was high. And as there was lots of the career and income, the police of a petition or search and guide staff was high and the job satisfaction degree in which relatively the employee and the other job group is high so that the case of being the former student incidence can be the poorest was shown rather than the facility security agent. As the interrelation analysis result job satisfaction was high, the change of occupation pseudo was low and the organizational commitment degrees was increased. The regression analysis result job satisfaction degree was exposed to reach the meaningful effect on the change of occupation pseudo and organizational commitment. It had an effect on the change of occupation pseudo as the task characteristic and office ambient level was low. It had an effect on the organizational commitment as the extend of satisfaction about the task characteristic and interpersonal relationship, complement, and office ambient level were high. If the research result of this time is integrated, the support of the political system including the interpersonal relationship thesis between top and bottom of the organized I and substantial complement actualization is urgently needed between the office given condition improvement effort in the country important facility defense manpower field and police of a petition and special guard.

• Journal of the Ergonomics Society of Korea
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• v.36 no.5
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• pp.579-587
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• 2017

Objective: The purpose of this study is to measure the workload of Korea coastal ship crew members, to investigate whether they are following work-break time regulations and to identify the main causes of their workload. Background: According to the US Coast Guard, about 33% of human casualties are reported to be due to fatigue, and 30% of marine casualties reported by the British Marine Accident Investigation Agency (MAIB) are attributed to crew fatigue. But the coastal ship are not managed for business hours and breaks despite the harsh environment. Method: The workload of duty crew members on the 100 domestic coastal vessels was measured. It was also investigated whether they are following domestic and international work-break time regulations. Finally, the marine accidents resulted from the fatigue of the crew was analyzed. Results: As a result of workload analysis, the workload on the 42~62% of the vessels exceeded the standard of working time on the related regulation. The workload increased with the number of inbound and outbound ports. Especially, in the system where there are two seafarers, the workload exceeded the working time requirement. As a result of the marine accidents analysis on 100 vessels, it was found that collision and grounding occurred due to fatigue, workload and drowsiness in 7 marine accidents out of 30 marine accidents. Conclusion: It is necessary for the shipping companies to introduce an operation management manual for the management of the crews' workload and reasonable crew arrangement. It is also required for crew members to easily record work times and for shipping companies to manage the record. It would be possible to prevent many marine accidents by providing adequate rest to the crews and flexibly adjusting their working hours. Application: The results of this study can be used as fundamental data to manage crews' fatigue and to make job management manuals.

• The Journal of the Convergence on Culture Technology
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• v.7 no.4
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• pp.113-122
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• 2021

This study begins on the basis of Jacques Lacan's article 『Logical Time and Assertions of Preemptive Certainty: A New Sophism』 published in the reissue of 『Art Note Les Cahiers d'Art』 in March 1945. In this paper, a guard presents an esoteric problem to three prisoners. If the problem is solved, the prisoner is released. A condition is given to solve a problem. Conversation between prisoners is prohibited, and the disc behind them cannot be seen. In this time and space, prisoners place themselves in logical time through the 'time of understanding' in order to become the chosen ones. We always live in logical time. We will argue the point at which Lacan destroys logical time in psychoanalysis. Time in Lacanian psychoanalysis transcends time divisions of the past, present, and future. Our time is always the past in the present. In Lacanian psychoanalysis, logical time is the time in the Other. The transcendence of the Lacanian psychoanalysis concept of time shows the deviation of logical time. In this text, We try to prove how Lacan contrasts psychoanalysis and the problem of time with time in the other. First, we will examine how logical time and impulse are related in psychoanalysis. Second, the postmortemity of the signifient (signifier) will be discussed. Third, Lacan psychoanalysis will present the transcendence of time. In conclusion, We will present the view that the time of Lacan psychoanalysis is flowing backwards. In Lacanian psychoanalysis, we try to prove that logical time is in the territory of the Other and is infinite time.

• Journal of Adhesion and Interface
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• v.17 no.1
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• pp.21-28
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• 2016

Foam-type biodegradable polyurethane adhesives were developed as a non-lethal weapon against illegal fishing boats. The adhesives were prepared from a hardener of polymeric methylene diphenyl diisocyanate (MDI) and a base composed of polyester and/or polyether polyols. In order to accelerate biodegradability, starch, dextrin, and amylase were added into the base, and which present about 34% degradability within 4 weeks confirmed by OECD 301C method. For proper mixing and corresponding prompt foam reaction, viscosities of hardener and base compositions were investigated in the temperature ranges from 0 to $50^{\circ}C$. For fast completion of the foam forming and corresponding adhesion, rising time was recorded in the same temperature range, and the rising time of the adhesive was varied within around 1 minute. T-peel adhesion tests with cotton fabrics were performed which showed 20.78 N/cm and 11.95 N/cm as the maximum and the average values, respectively.

• Journal of Radiation Protection and Research
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• v.48 no.2
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• pp.100-106
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• 2023

Background: As breast tissue expanders consist of metallic materials in the needle guard and ferromagnetic injection port, irradiation can produce radioactivation. Materials and Methods: A CPX4 (Mentor Worldwide LLD) breast tissue expander was exposed using the Versa HD (Elekta) linear accelerator. Two photon energies of 6 and 10 MV-flattening filter free (FFF) beams with 5,000 monitor units (MU) were irradiated to identify the types of radiation. Furthermore, 300 MU with 10 MV-FFF beam was exposed to the CPX4 breast tissue expander by varying the machine dose rates (MDRs) 600, 1,200, and 2,200 MU/min. To assess the instantaneous dose rates (IDRs) solely from the CPX4, a tissue expander was placed outside the treatment room after beam irradiation, and a portable radioisotope identification device was used to identify the types of radiation and measure IDR. Results and Discussion: After 5,000 MU delivery to the CPX4 breast tissue expander, the energy spectrum whose peak energy of 511 keV was found with 10 MV-FFF, while there was no resultant one with 6 MV-FFF. The time of each measurement was 1 minute, and the mean IDRs from the 10 MV-FFF were 0.407, 0.231, and 0.180 μSv/hr for the three successive measurements. Following 10 MV-FFF beam irradiation with 300 MU indicated around the background level from the first measurement regardless of MDRs. Conclusion: As each institute room entry time protocol varies according to the working hours and occupational doses, we suggest an addition of 1 minute from the institutes' own room entry time protocol in patients with CPX4 tissue expander and the case of radiotherapy vaults equipped with a maximum energy of 10 MV photon beams.