본 연구목적은 고등학생의 게임중독에 미치는 부모와의 관계, 스트레 스, 주관적 행복도의 영향력을 검증하는 것이다. 연구의 대상자는 한국방 정환재단이 주관하고 연세대 사회발전연구소에서 시행한 「한국 어린이· 청소년 행복지수」의 2021년 제12차 조사의 고등학교 청소년 2,272명을 연구의 대상자로 정하였다. 고등학생의 게임중독에 미치는 독립변인들의 직접효과 및 간접효과를 확인하기 위해 SPSS 26.0 및 PROCESS Macro를 사용하였다. 첫째, 고등학생의 부모와의 관계는 스트레스에 부 적 영향, 주관적 행복도에 정적 영향, 게임중독에 부적 영향을 주는 것으 로 확인되었다. 둘째, 스트레스는 주관적 행복도에 부적 영향, 게임중독 에 정적 영향을 미치는 것으로 나타났다. 셋째, 주관적 행복도는 게임중 독에 부적 영향을 주는 것이 규명되었다. 넷째, 부모와의 관계와 게임중 독 간의 관계 내에서 스트레스와 주관적 행복도는 부적인 매개효과를 보 였다. 따라서, 본 연구결과는 향후, 청소년들의 게임중독 및 과몰입을 예 방할 수 있는 교육지원 정책 마련 및 프로그램 운영에 도움이 될 것으로 기대된다.

This study numerically compares optimum solutions generated by element- and node-wise topology optimization designs for free vibration structures, where element-and node-wise denote the use of element and nodal densities as design parameters, respectively. For static problems optimal solution comparisons of the two types for topology optimization designs have already been introduced by the author and many other researchers, and the static structural design is very common. In dynamic topology optimization problems the objective is in general related to maximum Eigenfrequency optimization subject to a given material limit since structures with a high fundamental frequency tend to be reasonable stiff for static loads. Numerical applications topologically maximizing the first natural Eigenfrequency verify the difference of solutions between element-and node-wise topology optimum designs.

Purpose: The study aim was to understand the experiences of intensive care unit (ICU) nurses in labor union activities. Methods: A descriptive qualitative study and content analysis were conducted. The participants included nine ICU nurses who shared their experiences with labor union activities. The data were collected through in-depth interviews. Results: The experiences of ICU nurses with labor union activities encompassed five themes: “The Initial Step in Union Activities”, “Benefits Derived from Union Participation”, “Concerns Regarding Union Activities”, “The Non-Omnipotence of Unions”, and “Achieving Mutual Benefits through Union Activities”. Conclusion: The study findings revealed that ICU nurses strive to improve their work and the nursing environment through labor unions, despite facing negative perceptions of union involvement.

This study explores the impact of technostress on the intention to use telemedicine applications (apps) in the post-COVID19 era, a period marked by the rapid popularization of such apps to mitigate COVID19 infection risks. Utilizing the Technology Acceptance Model (TAM), the study identifies variables and proposes a research model. A questionnaire survey involving 364 adults is analyzed through Partial Least Squares-Structural Equation Modeling. Results indicate positive significance for variables linked to the TAM (perceived usefulness, perceived ease of use, attitude, and intention to use). Notably, techno-complexity negatively affects perceived ease of use, while techno-unreliability negatively impacts perceived usefulness and ease of use. Surprisingly, techno-uncertainty has a positive effect on both perceived usefulness and ease of use. Techno-overload, although negatively impacting perceived usefulness and ease of use, does not reach statistical significance. The study underscores the need to consider both positive and negative aspects, including technostress, when evaluating telemedicine app usage. Additionally, recognizing the varying impact of technostress based on users' ICT(Information and Communication Technology) confidence levels is crucial. Overall, these findings contribute academically to telemedicine app adoption literature and hold industrial significance by providing a user perspective on these apps.

최근, 국토교통부에서 시행한 “국가 보행교통 실태조사”로 인해 보행안전과 보행환경에 대한 중요성이 증가하고 있으며, 전반적으로 대로에서는 보행환경이 양호하나 생활도로에서는 보도가 미설치되거나 보도폭이 협소하여 보행환경이 미흡하고 보행 만족도도 낮은 것으며 생활도로의 약 34%가 유효보도폭 기준을 충족하지 못하고 있다고 조사되었다. 국가 주요 사회간접자본(SOC)인 도로, 교량, 터 널, 공공건물, 환승센터 등에 비하여 상대적으로 보행공간을 대상으로한 정보화 속도가 늦어 정보화 연구개발에 대한 추진이 시급한 실정이다. 이에 정부에서도 국가공간정보정책 기본계획에 따른 국가공간정보정책 시행계획이 확정되어 신산업 기반으로서의 역할과 안전한 시설관리를 위한 디지털 트윈 관련 기술개발 등에 투자를 확대하고, 디지털 트윈 등의 기반 정보인 고정밀 공간정보 생산 등 에 중점적으로 투자하고 있다. 현재 한국건설기술연구원, 서울시, 경기도 등에서 활용하고 있는 조사장비(PES, KRISS)는 도로포장(차 도)에서 상태 모니터링을 진행하고 있으나 이와 같은 장비들은 고가의 장비들로 실질적으로 사용하기에는 어려움이 있다. 또한, 보행 도로에서는 상태 모니터링을 수집할 장비가 없기 때문에, 보행 공간 경사, 노면 상태 등을 측정ㆍ수집하는 방법은 인력에게 의존해왔 다. 또한, 현재 보행자도로에 대한 서비스수준 산정 방식은 한국도로용량편람(2013)의 보행자시설편에서 제공하고 있는 산정 방식으로 도로용량편람에서 제시하는 보행자도로의 분석 방법을 적용하여 서비스수준을 산출할 경우, 차량과 동일한 교통량-속도-밀도 관계에 의존하여 산출하기 때문에 현실적인 보행자도로의 서비스수준을 반영하지 못하고 있는 실정이다. 이러한 문제로 인해 보행공간에 대 한 이용자의 안전 및 편의성에 대한 연구가 미흡한 상황이다. 따라서, 본 연구는 모바일매핑시스템(Mobile Mapping System)과 인공지 능(AI), 무인비행장치(Drone)를 활용한 보행공간 상태 모니터링 시스템 구축 방안을 제시하고자 한다.

본 연구의 목적은 노인의 삶의 만족도에 미치는 우울, 가족관계, 자아 존중감 간의 구조적 영향관계를 살펴보는 것이다. 한국보건사회연구원 및 서울대학교 사회복지연구소에서 추진한 「한국복지패널조사」의 2022년 17 차 조사에서 65세 이상의 노인 6,717명을 연구대상자로 지정하였으며, SPSS 26.0, JASP 0.18.0 및 Stata 16을 사용하여 빈도 및 기술통계, 상 관관계분석, 구조방정식 모델 경로분석을 행하였다. 첫째, 노인의 우울은 자아존중감과 삶의 만족도에 통계적으로 유의한 부적인 영향을 주었다. 둘째, 가족관계는 자아존중감 및 삶의 만족도에 정적인 영향을 미쳤다. 셋째, 자아존중감은 노인의 삶의 만족도에 정적인 영향을 주는 것으로 확 인되었다. 넷째, 우울은 자아존중감을 부분매개로 하여 삶의 만족도에 부 적인 영향을 미쳤고, 가족관계는 자아존중감을 부분매개로 하여 삶의 만 족도에 정적인 영향을 주었다. 다섯째, 노인의 소득수준에 따른 저소득층 가구 집단와 일반가구 집단에서 동일하게 노인의 우울은 자아존중감 및 삶의 만족도에 부적인 영향을 미치며, 가족관계는 자아존중감 및 삶의 만 족도에 정적인 영향을 주었고, 또한 노인의 자아존중감은 삶의 만족도에 유의한 정적 영향을 미쳤으며, 자아존중감은 독립변인인 우울, 가족관계 와 종속변인 삶의 만족도 간에서 전부 간접효과를 나타내었다. 본 연구결 과는 노인의 삶의 만족도 개선을 위해 사회복지정책 수립, 행정 개선, 관 련 프로그램 운영을 위한 기초자료가 될 수 있을 것이다.

In this study, an experimental analysis of noise reduction in road traffic by applying the Micro Grooving technique to concrete highway pavements is explored. Initiated in 1984 to address the aging and damage issues observed in South Korea's concrete highways, Micro Grooving is known for creating fine grooves on the cement pavement surface to increase friction, prevent hydroplaning, and inhibit ice formation, while reducing vehicle friction noise by 3∼5dB(A). It is determined from noise measurement results that the application of the Micro Grooving method can be expected to reduce roadside noise and enhance the safety of drivers' driving experience.

In this study, infrared thermometry techniques were used to conduct surface wetting performance tests (wicking tests) on micropillar structures with good fluid supply capabilities to enhance the critical heat flux. Wicking tests were conducted based on various micropillar shapes (i.e., diameter and spacing) to investigate the surface wetting performance near the boiling point of the fluid(~100°C). The surface temperature was increased from 20°C to 95°C, to examine the wicking performance The shape of the micropillars were quantified by the roughness and the effect of the roughness and temperature on the wicking performance was analyzed. As a result, we confirmed that the roughness of the micropillars increases the capillary pressure, improving the wicking performance. The sample D04 G10 with the highest roughness coefficient at room temperature (r=2.51) exhibited the highest wicking coefficient, showing a 170% improvement in wicking performance compared to D04G20 with the smallest roughness coefficient at room temperature(r=1.51). Additionally, the D04 G10 sample (r=2.51) recorded a 50% improvement in the wicking coefficient at the highest temperature(95°C) compared to room temperature(20°C). The wicking coefficient data will be utilized as a database for developing a new correlation for critical heat flux.

본 연구는 인도의 전통의학인 아유르베다와 중국의 중의학 사이의 유사점과 차이점을 통해 아유르베다의 다섯 원소아 ( 까샤, 바유, 떼자스, 아빠스, 쁘리띠위)와 중의학의 오행(수, 화, 목, 금, 토)의 개념을 중심으로 두 의학 체계의 기본 구조 와 생명력에 대한 이해를 돕고자 한다. 아유르베다에서는 세 가지 도샤와 일곱 가지 기본 조직(다뚜)을 통해 신체의 기능 과 질병을 설명하는 반면, 중의학은 다섯 원소와 장부의 상 호 작용을 중심으로 신체와 질병을 파악하였다. 두 체계 모 두 생명력 에너지와 신체의 다양한 조직 및 장기와의 관계를 중요시하며, 질병의 원인과 치료에 대한 접근 방식에서 유사 성이 있으며, 특히, 소화의 중요성과 감정 및 에너지 흐름과 의 관계를 중요시한다. 문화적 기후적 지리적 차이에서 오는 두 이론의 성립에 대한 차이로 인해 각기 다른 의학의 형태 를 가지고 있지만, 본질적인 면인 인간의 신체와 마음을 이 해하는데 유사한 방식을 사용함을 보여주며, 두 전통 의학 체계에 대한 깊은 이해와 추가 연구를 위한 기반을 제공한다.

Composite-based piezoelectric devices are extensively studied to develop sustainable power supply and selfpowered devices owing to their excellent mechanical durability and output performance. In this study, we design a leadfree piezoelectric nanocomposite utilizing (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 (BCTZ) nanomaterials for realizing highly flexible energy harvesters. To improve the output performance of the devices, we incorporate porous BCTZ nanowires (NWs) into the nanoparticle (NP)-based piezoelectric nanocomposite. BCTZ NPs and NWs are synthesized through the solidstate reaction and sol-gel-based electrospinning, respectively; subsequently, they are dispersed inside a polyimide matrix. The output performance of the energy harvesters is measured using an optimized measurement system during repetitive mechanical deformation by varying the composition of the NPs and NWs. A nanocomposite-based energy harvester with 4:1 weight ratio generates the maximum open-circuit voltage and short-circuit current of 0.83 V and 0.28 A, respectively. In this study, self-powered devices are constructed with enhanced output performance by using piezoelectric energy harvesting for application in flexible and wearable devices.

근대는 16세기부터 19세기까지 서유럽에 새로운 기풍과 제도가 진작되 어, 중앙집권적인 근대국가의 수립, 무역과 산업혁명을 통한 경제성장, 그 리고 국민의 정치참여가 확대된 것을 지칭한다. 그런데 동유럽과 북유럽은 조금 다른 길을 걸어왔다. 먼저 헝가리는 ‘선거왕제’ 아래 귀족들의 권한 이 왕권보다 강해 중앙집권화와 국민통합이 어려웠다. 폴란드도 귀족들이 ‘선거왕제’ 아래 국내 기반이 약한 외국인을 왕으로 선출하고, 귀족 개개 인이 ‘자유거부권’을 가질 정도의 막강한 권한을 갖고 상인 등 잠재적 경 쟁자를 억압함으로써, 경제발전과 국민통합이 어려웠다. 두 국가 모두 국 토 분할을 경험했으며, 20세기 들어와서야 겨우 독립을 얻었다. 반면 군사 강국 스웨덴은 18세기 러시아 패권에 밀려 쇠락하자, 서로 권력투쟁을 벌 이던 왕과 귀족들이 타협해 입헌군주제를 채택하고 뒤늦게 산업화를 추진 했다. 덴마크도 경쟁국인 스웨덴에 밀린 후 19세기 몰락 위기에 처하자, 입헌군주제와 자유무역주의를 채택해 국민통합을 이루고 뒤늦게 근대화에 동참했다. 결국 동유럽처럼 자신의 이익만 추구하는 귀족들이 약한 왕에게 책임을 전가하고 실제로 국가를 주도하면 근대의 진입이 늦어지며, 북유럽 과 같이 국가적 위기 상황 속에서 왕과 귀족이 연대하고 국민을 통합하면 서유럽과 같은 근대화에 성공할 수 있었다는 것을 알 수 있다.

This study developed an IoT-based agricultural well control system and demonstrated it through a control system in the current state of domestic open-field smart farms where systematic management is insufficient due to the difficulty of collecting accurate data such as agricultural water intake and usage. As a result, it was possible to derive the optimal control system test results according to the watering conditions for each schedule by conducting automatic control focusing on periods when there is no precipitation. This means that irrigation can be carried out smoothly during the time when irrigation is needed to improve crop quality and secure farm income, and as a result, it is possible to systematically manage and operate among demonstration farms connected to irrigation, resulting in a shortage of agricultural water and a resolution of supply imbalances.

In this study, we designed and manufactured a large angular contact ball bearing (LACBB) with low deformation using JIS-SUJ2 steel and analyzed changes in its structural characteristics and chemical composition upon heat treatment. The bearing was produced by hot forging and heat treatment including a quenching and tempering (Q/T) process, and its properties were analyzed using 4 mm thick specimens. A difference in the size distribution of the carbide in the outer and inner parts of the bearing was observed and it was confirmed that large and non-uniform carbide was distributed in the inner part of the bearing. After heat treatment, the hardness value of the outer part increased from 13.4 HRC to 61 HRC and the inner part increased from 8.0 HRC to 59.7 HRC. As a result of X-ray diffraction (XRD) measurements, the volume fraction of the retained austenite contained in the outer part was calculated to be 3.5~4.8 % and the inner part was calculated to be 3.6~5.0 %. The surface chemical composition and the content of chemical bonds were quantified through X-ray photoelectron spectroscopy (XPS), and a decrease in C=C bonds and an increase in Fe-C bonds were confirmed.

In zinc-air batteries, the gel polymer electrolyte (GPE) is an important factor for improving performance. The rigid physical properties of polyvinyl alcohol reduce ionic conductivity, which degrades the performance of the batteries. Zinc acetate is an effective additive that can increase ionic conductivity by weakening the bonding structure of polyvinyl alcohol. In this study, polymer electrolytes were prepared by mixing polyvinyl alcohol and zinc acetate dihydride. The material properties of the prepared polymer electrolytes were analyzed by Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Also, Electrochemical impedance spectroscopy was used to calculate ionic conductivity. The electrolyte resistances of GPE, 0.2 GPE, 0.4 GPE, and 0.6 GPE were 0.394, 0.338, 0.290, and 0.213 Ω, respectively. In addition, 0.6 GPE delivered 0.023 S/cm high ionic conductivity. Among all of the polymer electrolytes tested, 0.6 GPE showed enhanced cycle life performance and the highest specific discharge capacity of 11.73 mAh/cm2 at 10 mA. These results verified that 0.6 GPE improves the performance of zinc-air batteries.

Highly safe lithium-ion batteries (LIBs) are required for large-scale applications such as electrical vehicles and energy storage systems. A highly stable cathode is essential for the development of safe LIBs. LiFePO4 is one of the most stable cathodes because of its stable structure and strong bonding between P and O. However, it has a lower energy density than lithium transition metal oxides. To investigate the high energy density of phosphate materials, vanadium phosphates were investigated. Vanadium enables multiple redox reactions as well as high redox potentials. LiVPO4O has two redox reactions (V5+/V4+/V3+) but low electrochemical activity. In this study, LiVPO4O is doped with fluorine to improve its electrochemical activity and increase its operational redox potential. With increasing fluorine content in LiVPO4O1-xFx, the local vanadium structure changed as the vanadium oxidation state changed. In addition, the operating potential increased with increasing fluorine content. Thus, it was confirmed that fluorine doping leads to a strong inductive effect and high operating voltage, which helps improve the energy density of the cathode materials.

본 연구에서는 고투과성 및 높은 염 제거율을 가지는 역삼투막의 성능향상을 위하여 다양한 첨가제 및 계면중합 시 경화 온도 및 시간에 따른 특성평가에 대한 연구가 수행되었다. 첨가제가 없는 막과 첨가제를 첨가한 막의 모폴로지는 모 두 “ridge-and-valley” 구조를 나타내어, 폴리아미드 층이 다공성 지지층 표면에 성공적으로 중합되었음을 확인하였다. 또한 2-Ethyl-1,3-hexanediol (EHD) 첨가함으로써 향상된 친수성과 수투과율 가졌으며, 이는 접촉각 측정을 통해서 확인되었다. 최 종적으로 97.78%와 98.7%의 NaCl 및 MgSO4 제거율과 3.31 L/(m2⋅h⋅bar)의 높은 수투과율을 가진 고투과성 계면중합막을 제조하였다.

PURPOSES : Basic research to calculate the appropriate gap acceptance for autonomous vehicles at merging section. Research on whether users prefer short or long gap acceptance. METHODS : Using a driving simulator, experience autonomous driving with different gap acceptance in different weather condition, and analyze which gap acceptance is preferred using survey and biometric data. RESULTS : Regardless of the weather condition, long gap acceptance was preferred, and difference was especially clear in rainy or foggy situation. CONCLUSIONS : It was analyzed that users prefer long gap acceptance over short gap acceptance, and that they feel less frustrated due to long gap acceptance when weather condition is poor.

The levels of Indoor radon can increase in newly built apartments that mainly use construction materials such as concrete. However, radon measurement in newly built buildings has only been implemented recently, and there is a lack of sufficient data for radon management purposes. This study aimed to determine the levels of indoor radon in newly built apartments by regions, sizes of household, and floor (lower, middle, upper floor), and to explore the trend of radon reduction by time according to ventilation methods. Indoor radon was measured in 48 households in four regions (Gyeonggi-do and Gangwon-do). Measurements were performed for 48 hours and 24 hours under closed and ventilated conditions using real-time measurement devices FRD400 and RAD7, respectively. To analyze changes in radon concentration by floors, data were collected by dividing households into lower, middle, and upper floors according to their vertical height. The concentrations of indoor radon ranged from 12.1 Bq/m3 to 559.0 Bq/m3 when windows were closed and 12.0 Bq/m3~500.0 Bq/m3 when ventilated (including both mechanical and natural ventilation). On average, the concentration of closed conditions of household when sealed (arithmetic average 185.3 Bq/m3) was 1.5 times higher than the concentration during ventilation (including mechanical and natural ventilation: 123.8 Bq/m3), and around three times higher than the average for mechanical ventilation (65.7 Bq/m3). It was found that the indoor radon concentration statistically increased as the height increased and the size of the house became smaller. Typically, it took 7 to 8 hours to exceed the standard of 148 Bq/m3 after windows were closed. It decreased to less than 148 Bq/m3 within 3 to 4 hours after operating the mechanical ventilation system. However, in the case of natural ventilation, it takes more than 24 hours to reach below the standard value, and the concentrations stagnated after 24 hours. In conclusion, radon concentration in narrow spaces can be relatively high if ventilation is not sufficient due to the nature of apartments with wall-type structures. Therefore, it is necessary to prepare various radon reduction measures according to floor, size, and ventilation methods.

In the (3,3) close combat model based on the Lanchester Square Law, this study proposes a plan to optimally allocate residual combat power after the battle to other battlefields. As soon as the two camps of three units can grasp each other's information and predict the battle pattern immediately after the battle began, the Time Zero Allocation of Force (TZAF) scenario was used to initially allocate combat power to readjust the combat model. It reflects travel time, which is a "field friction" in which physical distance exists from battlefields that support combat power to battlefields that are supported. By developing existing studies that try to examine the effect of travel time on the battlefield through the combat model, this study forms a (3,3) combat model, which is a large number of minimum units. In order to achieve the combat purpose, the principle of optimal combat force operation is presented by examining the aspect that support combat power is allocated to the two battlefields and the consequent battle results. Through this, various scenarios were set in consideration of the travel time and the situation of the units, and differentiated results were obtained. Although the most traditional, it can be used as the basic logic of the training or the commander's decision-making system using the actual war game model.

To understand microorganism effects on wild mushroom fruiting bodies, we investigated the fungi in hyphosphere soil supporting wild mushroom species Cortinarius violaceus, Amanita hemibapha, Laccaria vinacelavellanea, and Amanita verna found in the Gotjawal area of Jeju Island. Fungal species identification based on morphological traits and molecular analysis of ITS, LSU rDNA, and -tubulin gene sequences resulted in isolation and identification of eleven fungal species previously unrecorded in Korea. These newly-recorded species are: Arthrinium kogelbergensis, Kalmusia longisporum, Keithomyces carneum, Neopyrenochaeta cercidis, Penicillium ranomafanaense, Phomatodes nebulosa, Pyrenochaeta nobilis, Tolypocladium album, Talaromyces kendrickii, Talaromyces qii, and Umbelopsis gibberispora, and their morphological characteristics and phylogenetic positions are described.