• Journal of Radiation Protection and Research
• /
• v.48 no.1
• /
• pp.9-14
• /
• 2023

Background: The detectors of both computed radiography (CR) and direct digital radiography (DR) have a wide dynamic range that could tolerate high values of exposure factors without an adverse effect on image quality. Therefore, this study aims to assess patient radiation dose and proposes institutional diagnostic reference levels (DRLs) for two teaching hospitals in Ghana. Materials and Methods: CR and DR systems were utilized in this study from two teaching hospitals. The CR system was manufactured by Philips Medical Systems DMC GmbH, while the DR system was manufactured by General Electric. The entrance skin doses (ESDs) were calculated using the standard equation and the tube output measurements. Free-in-air kerma (µGy) was measured using a calibrated radiation dosimeter. The proposed institutional DRLs were estimated using 75^th percentiles values of the estimated ESDs for nine radiographic projections. Results and Discussion: The calculated DRLs were 0.4, 1.6, 3.4, 0.5, 0.4, 1.1, 1.0, 1.2, and 1.7 mGy for chest posteroanterior (PA), lumbar spine anteroposterior (AP), lumbar spine lateral (LAT), cervical spine AP, cervical spine LAT, skull PA, pelvis AP, and abdomen AP, respectively in CR system. In the DR system, the values were 0.3, 1.6, 3.1, 0.4, 0.3, 0.7, 0.6, 0.9, and 1.3 for chest PA, lumbar spine AP, lumbar spine LAT, cervical spine AP, cervical spine LAT, skull PA, pelvis AP, and abdomen AP, respectively. Conclusion: Institutional DRLs in nine radiographic projections have been proposed for two teaching hospitals in Ghana for the first time. The proposed DRLs will serve as baseline data for establishing local DRLs in the hospitals and will be a valuable tool in optimizing patient doses.

• Journal of Korea Water Resources Association
• /
• v.41 no.6
• /
• pp.619-628
• /
• 2008

Bank protection is a structure constructed to protect directly embankment breakage and erosion by river flow. Traditionally, the type of bank protection has been decided by practitioner's subjective and empirical judgement, which often causes problems after construction. Recently, however, it becomes important to consider not only physical protection but also environment. Various types of bank protection for environment-friendly river are now available. Thus, there is a need for more objective and quantitative decision method for bank protection work. This study adopts the analytic hierarchy process (AHP) to improve the objectiveness in the decision of bank protection work. Criteria for stability, economy, construction, environment are identified and a standardized process is presented for field application. With the proposed method, one can prioritize various bank protection works and make the optimal decision. We believe that the method can serve as a useful tool for river engineers in practice.

• Progress in Superconductivity and Cryogenics
• /
• v.23 no.4
• /
• pp.19-24
• /
• 2021

The low normal zone propagation velocity (NZPV) of high-temperature superconducting (HTS) tape leads to a quench protection problem in HTS magnet applications. To overcome this limitation, various studies were conducted on HTS coils without turn-to-turn insulation (NI coils) that can achieve self-protection. On the other hand, NI coils have some disadvantages such as slow charging and discharging time. Previously, the HTS coils with turn-to-turn insulation (INS coils) were operated in power supply (PS) driven mode, which requires physical contact with the external PS at room-temperature, not in persistent current mode. When a quench occurs in INS coils, the low NZPV delays quench detection and protection, thereby damaging the coils. However, the rotary HTS flux pump supplies the DC voltage to the superconducting circuit with INS coils in a non-contact manner, which causes the INS coils to operate in a persistent current mode, while enabling quench protection. In this paper, a new protection characteristic of HTS coils is investigated with INS coils charging through the rotary HTS flux pump. To experimentally verify the quench protection characteristic of the INS coil, we investigated the current magnitude of the superconducting circuit through a quench, which was intentionally generated by thermal disturbances in the INS coil under charging or steady state. Our results confirmed the protection characteristic of INS coils using a rotary HTS flux pump.

• The Research Journal of the Costume Culture
• /
• v.31 no.5
• /
• pp.692-704
• /
• 2023

This study analyzed 214 sports knee braces found on Chinese websites between October 2022 and November 2022 to assess product type (impact protection material, fastening method, and protection method), material composition, size, weight, and main characteristics. The product type was further categorized according to (1) use of hard guard and soft guard protection method; (2) cover type, strap type, and slip-on type fastening method; and (3) pressure type and support type protection method. It also noted the physical shock protection materials used, including foam (EVA or polyurethane) attached to joints as a buffer material and plastic (TPU or PP) that protects the user's knee from external impacts. The study found that the materials that primarily comprise sports knee braces are a combination of nylon, polyester, and neoprene. Additionally, it found that most sports knee braces available on the market are available in three sizes based on knee circumference: M (35-38cm), L (38-41cm), and XL (41-44cm), while some products are available in one size only. Furthermore, the majority of the 214 products studied weighed 200g, followed by 1,000g. Finally, in terms of product characteristics, many sports knee braces utilize ring-shaped silicone pads to distribute the load pressure on the knees or incorporate sturdy adhesive velcro to improve knee stability.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
• /
• v.35 no.4
• /
• pp.230-242
• /
• 2024

Objectives: Depression and anxiety are emotional difficulties that are common among adolescents. Adolescents suffering from depression and anxiety can exhibit problems such as antisocial behavior, aggression, and academic slump. This study aimed to explore the factors influencing adolescents' depression and anxiety during the coronavirus disease 2019 (COVID-19) pandemic. Methods: This study examined the data from an online student health survey conducted by the Ministry of Education in 2022. The survey participants were 131194 students ranging from the first grade of middle school to the third grade of high school. The influence of each variable on depression and anxiety was examined. Results: Factors that predicted depression and anxiety were sex (female), grade level (higher), financial difficulties (existing or unknown), physical activity (higher), sleep time (shorter), media usage time (higher), family/friends relationship (worse), and change in the health status of family, friends, and oneself due to COVID-19 (worse). Conclusion: These results may help identify patterns of depression and anxiety among adolescents caused by COVID-19 and maximize the intervention effect.

• The Journal of Korean Physical Therapy
• /
• v.35 no.1
• /
• pp.1-7
• /
• 2023

Purpose: This study sought to investigate the perceptions and service needs of tele-physical therapy among people in their 50s and older in Korea. Methods: Subjects were inducted during a 14-day survey of 104 people over the age of 50 in Korea and were administered a questionnaire consisting of 14 questions about their general characteristics and another 14 questions about tele-physical therapy. Results: The general characteristics of the participants (participants' gender, whether they were single or married, number of cohabiting families, final education, major, job, physical therapy experience, tele-physical therapy experience, presence of a physical therapy worker among relatives, subjective health awareness, chronic disease conditions if any, frequency of drinking, and smoking) were investigated. Among the perceptions of the subjects about tele-physical therapy, the score of 'awareness' was the lowest, and that of 'resolving restrictions on hospital visits' was the highest. In an analysis of the correlation between perceptions and needs, there was a significant correlation with factors other than 'awareness' and 'information protection' factors. The regression analysis of necessity and factors revealed that the awareness of necessity increased as the intention to use, health improvement, and time efficiency improved. Conclusion: These findings presented the perception and necessity of tele-physical therapy for adults in their 50s or older in Korea. These results will help confirm the demand for tele-physical therapy in this age group in Korea and the need to improve the available physical therapy services.

• Journal of the Society of Disaster Information
• /
• v.5 no.2
• /
• pp.24-37
• /
• 2009

In the political and economic circles of our society, the security and secretary is always accompanying the society leaders, like shadows. The job of the security and secretary is a very difficult one that requires comprehensive and extensive capability and talent. From results of the prior studies, qualities of the security and secretary are divided into three groups. i.e. personal qualities, mental qualities and physical qualities. Each quality can be summarized as follows. Firstly, personal qualities mean honesty, responsibility, initiative, work ethic, sense of duty, modest attitude, kindness and loyalty. Secondly, mental qualities represent agility & composure, judgement, adaptability, memory, prediction, accuracy & reliability, observation and secret. Finally, physical qualities such as health, cleanliness, decent appearance, good feeling voice, physical strength and Martial arts for Protection. The security and secretary equipped with the above three requisites can be said to be the most ideal the security and secretary whom this age want and need.

• Journal of Korean Society on Water Environment
• /
• v.27 no.2
• /
• pp.218-227
• /
• 2011

The objective approach for assessment of stream naturalness is an essential part of the stream restoration project. This study proposes the methodology for the assessment of stream naturalness considering physical, biological and chemical factors. Physical factors consists of riffle and pool, river bed material, bank protection, floodplain vegetation and levee materials; biological factors are benthic macroinvertebrate, KSI (Korean Saprobic Index), and IBI (Index of Biological Integrity) and chemical factors are pH, DO (dissolved oxygen), and TP (total phosphorus). This procedure is applied to the Mokgamcheon. As a result, the downstream of Mokgamcheon (zone I) needs the prompt improvement of stream naturalness, compared to the others (zone II and III). This evaluation technique will be an effective tool to quantify the stream naturalness and can be used to set the target of stream restoration project.

• Journal of Advanced Navigation Technology
• /
• v.21 no.5
• /
• pp.459-465
• /
• 2017

In this paper, we introduce the design consideration of the lightning induced transient protection circuit for the indirect lightning strike on the avionics equipment. The lightning induced surge voltage, which is so-called as indirect effects of lightning, may cause a functional failure or physical damage to the electrical and electronic equipment of aircraft. In order to protect the electrical and electronic equipment of aircraft from the indirect effects of lightning, we should analyze the effect of lightning strike on aircraft and consider applying protection design for each avionics device. However, lightning induced transient protection circuits can have unintended consequences because parasitic inductance elements are exist in PCB and TVS diodes. In this paper, we introduce the design method of the protection circuit considering the parasitic inductance of the protection circuit. In addition, we show the result of verification test performed to validate the protection circuits for indirect effects of lightning.

• Journal of Advanced Marine Engineering and Technology
• /
• v.40 no.7
• /
• pp.599-604
• /
• 2016

Cathodic protection was first introduced as a technology for preventing the corrosion of metals in seawater and underground environments in the early 19th century, eventually leading to the introduction of cathodic protection to the reinforced concrete technology sector in the 1970s. In the 1990s, it was demonstrated that the effectiveness of corrosion protection had increased through a number of developments and studies. Recently, cathodic protection was applied to some reinforced concrete structures and has gradually expanded in scope in South Korea. Technical expertise is necessary to understand the underlying electrochemical principles and also because cathodic protection is important for normal physical maintenance. Therefore, in this study, we introduce the technical details and examples of applications of the cathodic protection of reinforced concrete, including the basic theory, principles, and other criteria.