목적: 최근 다양한 분야에서 개인차를 통한 업무와 교육의 효율성을 증대시키기 위한 연구가 많이 소개되고 있다. 이러한 개인차를 나타내는 것 중 하나가 성격이다. 이에 본 연구는 인간 이해를 위한 성격유형 검사인 MBTI(Myers-Briggs Type Indicator) 성격유형을 사용하여 성격에 따른 시기능훈련 전, 후 양안시기능 향상도를 알아보고자 하였다. 방법 : 20대 성인 남녀 41명을 대상으로 MBTI 성격유형을 분류하고 개인별 시기능훈련 도구를 선정하여 시기 능훈련을 실시한 후, 시기능훈련 전, 후 양안시기능 검사값을 비교를 하였다. 결과 : 시기능훈련 전, 후 양안시기능 검사를 통해 MBTI 4가지 기질 간의 양안시기능 변화량을 비교한 결과 조절래그 변화량에서 유의한 차이가 나타났다. SP기질의 조절래그 변화량의 평균이 SJ기질의 조절래그 변화량 평 균보다 음의 방향으로 높게 나타났으며 통계적으로 유의한 차이를 보였다(p<0.050). 시기능훈련 전, 후 양안시기 능 검사를 통해 MBTI 선호지표 간의 양안시기능 변화량을 비교한 결과 판단 지표인 사고(T)-이상(F)에서는 원거 리 양성융합버전스 분리점, 회복점, 융합용이성, 단안 조절력 검사에서 사고형의 향상도가 이상형의 향상도보다 높게 나타났으며, 통계적으로 유의한 차이를 보였다(p<0.050). 결론 : 이상의 결론에서 MBTI 성격유형 간의 시기능훈련 전, 후 양안시기능 변화량에 차이가 있음을 확인할 수 있었으며, 이를 통하여 성격유형에 따라서 시기능훈련의 변화량이 다를 수 있으며, 개인의 성격유형을 반영한 시기능훈련 방식을 고안한다면 더 효과적이고 체계적인 시기능훈련 효과를 예상하고 적용시킬 수 있을 것으로 사 료 된다.

Recently, unmanned logistics delivery systems, such as UAV (Unmanned Aerial Vehicle, written as drone below) and autonomous robot delivery systems, have been implemented in many countries due to the rapid development of autonomous driving technology. The development of these new types of advanced unmanned logistics delivery systems is essential not only to become a leading logistics company but also to secure national competitiveness. In this paper, the application of the unmanned logistics delivery system was investigated in terms of market trends, overall technology level of last mile delivery drone and autonomous delivery robot. The direction of response to changes in the last mile delivery service market was checked through a comparison of the technological level between domestic companies that produce last mile devices and advanced foreign companies. As a result of this technology level analysis, the difference between domestic companies and advanced companies was shown using tables and figures to show their relative levels. The results of this analysis reflect the opinions of experts in the field of last-mile delivery technology. In addition, the technology level of unmanned logistics delivery systems for each country was analyzed based on the number of related technology patents. Lastly, insights for the technology level analysis of unmanned last mile delivery systems were proposed as a conclusion.

This study attempts to analyze the economic impact of the service robot industry using Input-Output analysis, which is conducted based on Demand-driven model, the Leontief price model, the Backward and Forward Linkage Effects, and the Exogenous Methods. In a Demand-driven model analysis, we can conclude that the service robot industry contains characteristics of both the manufacturing industry and the service industry, which causes a positive impact on the overall industry by compensating for the weaknesses of the two industries. The Leontief price analysis indicates when wages in the service robot industry increase, prices related to robot manufacturing also increase. Also, when profits in the service robot industry increase, prices related to service provision increase, too. The Backward and Forward Linkage Effects analysis shows that the service robot industry is highly sensitive to the current economic condition and has a great influence on the service industry. The service robot industry can highlight the aspect of service characteristics when the manufacturing industry is in recession and vice versa. In addition, the service robot industry can be regarded as a value-adding and domestic economy promoting industry which utilizes knowledge of information and communication technologies. It is important to foster the service robot industry in South Korea, which is in economic recession to provide an opportunity to stimulate the growth of both service and robot industries.

The function of coolant in machining is to reduce the frictional force in the contact area in between the tool and the material, and to increase the precision by cooling the work-piece and the tool, to make the machining surface uniform, and to extend the tool life. However, cutting oil is harmful to the human body because it uses chlorine-based extreme pressure additives to cause environmental pollutants. In this study, the effect of cutting temperature and surface roughness of titanium alloy for medical purpose (Ti-6Al-7Nb) in eco-friendly ADL slot shape machining was investigated using the response surface analysis method. As the design of the experiment, three levels of cutting speed, feed rate, and depth of cut were designed and the experiment was conducted using the central composite planning method. The regression expressions of cutting temperature and surface roughness were respectively obtained as quadratic functions to obtain the minimum value and optimal cutting conditions. The values from this formula and the experimental values were compared. As a result, this study makes and establishes the basis to prevent environmental pollution caused by the use of coolant and to replace it with ADL (Aerosol Dry Lubricant) machining that uses a very small amount of vegetable oil with high pressure.

본 연구는 자살을 생각하는 학생들의 대학생활 적응, 심리상담 실태, 그리고 자살생각 영향요인을 파악 하고자 한다. 편의표집이나 특정전공자들을 대상으로 할 경우 자살생각 대학생들의 실태를 파악하기 어려 운 제한점이 있다. 따라서 비임상군인 재학생 전수를 대상으로 실시한 실태조사 결과를 분석함으로써 대학 생 자살생각의 심각성을 파악하고자 했다. 본 연구는 서울 소재 A대의 <학생실태 및 요구도 조사>(2021년 5~6월 실시, 재학생의 74.8%인 4,129명 응답)의 데이터를 사용하였다. 본 연구는 응답결과 중에서 기본정 보, 정신건강, 상담, 학교생활에 관한 내용을 중심으로 ‘자살을 생각한 집단’과 ‘자살을 생각하지 않은 집단’ 간의 차이를 비교하여 분석하였다. 자살을 생각한 집단은 혼자 거주하는 비율이 높고, 흡연량이 많고, 스마 트폰 사용 장애를 겪는 나타났다. 그리고 그들은 입학만족도, 전공만족도, 자아존중감 및 교우관계에 대한 만족도가 낮았고, 학업스트레스가 높은 것으로 나타났다. 또한 그들은 교내보다는 교외에서 심리상담을 받 은 비율이 높은 것으로 나타났다. 한편, 자살생각에 영향을 미치는 요인으로는 성별, 학년, 흡연량, 입학만족 도, 학업스트레스, 자아존중감, 심리상담 여부 등인 것으로 확인되었다. 이런 연구결과를 토대로 본 연구는, 심리상담에 대한 접근성을 제고할 수 있는 상담시스템의 구축과 자살위험군에 대한 체계적인 관리시스템의 구축을 제언하였다.

In a group-testing method, instead of testing a sample, for example, blood individually, a batch of samples are pooled and tested simultaneously. If the pooled test is positive (or defective), each sample is tested individually. However, if negative (or good), the test is terminated at one pooled test because all samples in the batch are negative. This paper considers a queueing system with a two-stage group-testing policy. Samples arrive at the system according to a Poisson process. The system has a single server which starts a two-stage group test in a batch whenever the number of samples in the system reaches exactly a predetermined size. In the first stage, samples are pooled and tested simultaneously. If the pooled test is negative, the test is terminated. However, if positive, the samples are divided into two equally sized subgroups and each subgroup is applied to a group test in the second stage, respectively. The server performs pooled tests and individual tests sequentially. The testing time of a sample and a batch follow general distributions, respectively. In this paper, we derive the steady-state probability generating function of the system size at an arbitrary time, applying a bulk queuing model. In addition, we present queuing performance metrics such as the offered load, output rate, allowable input rate, and mean waiting time. In numerical examples with various prevalence rates, we show that the second-stage group-testing system can be more efficient than a one-stage group-testing system or an individual-testing system in terms of the allowable input rates and the waiting time. The two-stage group-testing system considered in this paper is very simple, so it is expected to be applicable in the field of COVID-19.

As the environmental impacts of fossil fuel energy sources increase, the South Korean government has tried to change non-environmental- friendly enery sources to environmental-friendly energy sources in order to mitigate environmental effects, which lead to global warming and air pollution. With both a limited budget and limited time, it is essential to accurately evaluate the economic and environmental effects of renewable energy projects for the efficient and effective operation of renewable energy plants. Although the traditional economic evaluation methods are not ideal for evaluating the economic impacts of renewable energy projects, they can still be used for this purpose. Renewable energy projects involve many risks due to various uncertainties. For this reason, this study utilizes a real option method, the Geske compound model, to evaluate the renewable energy projects on Jeju Island in terms of economic and environmental values. This study has developed an economic evaluation model based on the Geske compound model to investigate the influences of flexibility and uncertainty factors on the evaluation process. This study further conducts a sensitivity analysis to examine how two uncertainty factors (namely, investment cost and wind energy production) influence the economic and environmental value of renewable energy projects.

타임루프는 등장 인물에게 반복되는 시간의 주기를 경험하게 하는 장치로, 주기적 시간에서의 반복적 실패 를 통해서 문제를 파악하고 해결하는 과정이 드러나 있는 것이 특징이다. 본 논문에서는 타임루프 장치를 통한 반복이 게임의 전개와 플레이어의 경험에 어떤 작용을 하는지 알아보기 위해 게임 ‘12 Minutes’을 중심 으로 게임요소와 스토리텔링을 살펴보았다. 이를 위해 게임에서 타임루프로 인지되는 인터랙션이 무엇이고, 그 안에서 플레이어 캐릭터와 플레이어의 위치, 게임의 목표와 분기점이 어떻게 변화하는지 분석하였다. 그 결과, 다음과 같은 사실을 알게 되었다. 첫째, 타임루핑 게임에서 반복적 인터랙션은 오브젝트와 플레이어, 캐릭터 사이에 일어나는데, 루핑을 알고 있는 존재는 플레이어 캐릭터와 플레이어로 타임루핑은 플레이어 차원과 플레이어 캐릭터 차원에서 일어난다는 점이다. 둘째, 게임에서 타임루프는 다중의 서사를 만들어내 는 플랫폼으로 문제해결을 위한 다양한 시도가 가능하고, 플레이어가 가상 세계에 행하는 행위를 통해 자신 의 욕망하는 바를 잘 드러낼 수 있도록 기능하는 장치라는 것이다.

To mitigate the environmental impacts of the energy sector, the government of South Korea has made a continuous effort to facilitate the development and commercialization of renewable energy. As a result, the efficiency of renewable energy plants is not a consideration in the potential site selection process. To contribute to the overall sustainability of this increasingly important sector, this study utilizes the Black-Scholes model to evaluate the economic value of potential sites for off-site wind farms, while analyzing the environmental mitigation of these potential sites in terms of carbon emission reduction. In order to incorporate the importance of flexibility and uncertainty factors in the evaluation process, this study has developed a site evaluation model focused on system dynamics and real option approaches that compares the expected revenue and expected cost during the life cycle of off-site wind farm sites. Using sensitivity analysis, this study further investigates two uncertainty factors (namely, investment cost and wind energy production) on the economic value and carbon emission reduction of potential wind farm locations.

The paint removal of fighter jets is just as important as the painting, because perfect paint removal ensures the quality of the exterior painting on the aircraft. However, the current conditions for paint removal work of the ROKAF’s are poor. It is identified that the painting process currently implemented by the ROKAF is not only exposed to harmful compounds such as harmful dust and hexavalent chromium, but also consumes a lot of water. Thus, the introduction of advanced facility is considered. This study compares the fighter jets painting removal process currently applied by the Korean Air Force with the improved laser coating removal process of the US Air Force, and conducts an incremental analysis to perform economic analysis for the introduction of advanced facility. Four scenarios were envisioned on the premise of an increase in the number of fighters in the future, incremental analysis shows that laser coating removal method is advantageous in all scenarios. In addition, it is recommended that paint removal cycle keeps the current 12-year and the outsourcing amount to civilian depot is reduced.

PURPOSES : The primary purpose of this study is to establish a crash probability model based on a statistical method that explains the relationship between regressor and explanatory variables using both fixed and random effects to control the heterogeneous characteristics of the observed data. In addition, an attempt was made to discover the leading cause of crashes by vehicle type, including passenger car, bus, truck, and trailer. METHODS : The levels of each route and day of the week are grouped using raw expressway crash data for 10 years from 2012 to 2021, and a multilevel mixed-effect logit model is constructed for each vehicle type assuming that the error terms are derived from the hierarchical structure of the group to which they belong. RESULTS : Speeding and obstacles on the road are significant factors that increase the probability of passenger car crashes, and bus crashes have a high rate at toll gates on weekdays. CONCLUSIONS : The multilevel mixed-effect logit model derived in the study has higher accuracy than the general logit model, confirming that mixed-effect analysis is plausible.

PURPOSES : The turning movement of vehicles is directly affected by such factors as vehicle length, wheelbase, steering angle, articulated angle, and wheel steering. Therefore, it is necessary to analyze the impact of changes in each factor on the turning of the vehicle. Because a vehicle with a long body, such as an articulated bus, makes a wide turn, this study analyzes the swept path of the driving vehicle considering the specifications of the vehicle. METHODS : This study was conducted by dividing driving routes into four routes of two-lane four-way roundabouts, and the turning conditions were examined for six types (Type 1–6) that simulated actual articulated bus data. The same vehicle specifications as those of the actual articulated bus were applied to the road design simulation (AutoTURN Pro), and the width of the swept path for the articulated bus was investigated based on the wheel steering control. Using a virtual reference line for dividing the inscribed circle into lanes of the roundabout by 5°, the driving width of the swept path was measured and the angle at which the driving width was largest during driving through the turning intersection was examined. In addition, the changes in the driving width of the swept path according to the wheel steering control under the same wheel turning conditions, as well as the articulated and steering angles, were investigated. RESULTS : The driving width of the swept path for the vehicle (Type 1) with the front wheel control function being an all-wheel system was less than that of an articulated bus with the largest driving width of 15° after entering the roundabout and 15° before entering the roundabout (Type 2). Furthermore, although the specifications of the vehicles were the same, it was determined that Type 5 was superior to Type 6 after reviewing the driving width in light of changes in the steering and articulated angles. CONCLUSIONS : The results of this study are expected to contribute to the field of road design considering traffic safety when large vehicles, such as articulated buses, turn on roundabouts or curved road sections.

PURPOSES : Local governments in Korea, including Incheon city, have introduced the pavement management system (PMS). However, the verification of the repair time and repair section of roads remains difficult owing to the non-existence of a systematic data acquisition system. Therefore, data refinement is performed using various techniques when analyzing statistical data in diverse fields. In this study, clustering is used to analyze PMS data, and correlation analysis is conducted between pavement performance and influencing factors. METHODS : First, the clustering type was selected. The representative clustering types include K-means, mean shift, and density-based spatial clustering of applications with noise (DBSCAN). In this study, data purification was performed using DBSCAN for clustering. Because of the difficulty in determining a threshold for high-dimensional data, multiple clustering, which is a type of DBSCAN, was applied, and the number of clustering was set up to two. Clustering for the surface distress (SD), rut depth (RD), and international roughness index (IRI) was performed twice using the number of frost days, the highest temperature, and the average temperature, respectively. RESULTS : The clustering result shows that the correlation between the SD and number of frost days improved significantly. The correlation between the maximum temperature factor and precipitation factor, which does not indicate multicollinearity, improved. Meanwhile, the correlation between the RD and highest temperature improved significantly. The correlation between the minimum temperature factor and precipitation factor, which does not exhibit multicollinearity, improved considerably. The correlation between the IRI and average temperature improved as well. The correlation between the low- and high-temperature precipitation factors, which does not indicate multicollinearity, improved. CONCLUSIONS : The result confirms the possibility of applying clustering to refine PMS data and that the correlation among the pavement performance factors improved. However, when applying clustering to PMS data refinement, the limitations must be identified and addressed. Furthermore, clustering may be applicable to the purification of PMS data using AI.

Recently, the construction of tall buildings utilized by high strength-concrete in the whole world is tending to be on the rise. The application of high-rise structural system in buildings results in the excellent cut-down effect in construction materials due to section reduction. Therefore, in order to investigate the CO2 and resource reduction effect for the high-rise structural system, comparisons of GWP and ADP in embodied energy of structural materlais between 4 type of high-rise structural system have been performed. As a result, GWP emission increased in the order of steel structure outrigger system, RC shear wall system, and RC outrigger system. On the other hand, ADP emissions increased in the order of RC shear wall system, RC outrigger system, and steel structure outrigger system.

PURPOSES : To efficiently manage pavements, a systematic pavement management system must be established based on regional characteristics. Suppose that the future conditions of a pavement section can be predicted based on data obtained at present. In this case, a more reasonable road maintenance strategy should be established. Hence, a prediction model of the annual surface distress (SD) change for national highway pavements in Gangwon-do, Korea is developed based on influencing factors. METHODS : To develop the model, pavement performance data and influencing factors were obtained. Exploratory data analysis was performed to analyze the data acquired, and the results show that the data were preprocessed. The variables used for model development were selected via correlation analysis, where variables such as surface distress, international roughness index, daily temperature range, and heat wave days were used. Best subset regression was performed, where the candidate model was selected from all possible subsets based on certain criteria. The final model was selected based on an algorithm developed for rational model selection. The sensitivity of the annual SD change was analyzed based on the variables of the final model. RESULTS : The result of the sensitivity analysis shows that the annual SD change is affected by the variables in the following order: surface distress ˃ heat wave days ˃ daily temperature range ˃ international roughness index. CONCLUSIONS : An annual SD change prediction model is developed by considering the present performance, traffic volume, and climatic conditions. The model can facilitate the establishment of a reasonable road maintenance strategy. The prediction accuracy can be improved by obtaining additional data, such as the construction quality, material properties, and pavement thickness.

PURPOSES : The aim of this study is to evaluate the stripping resistance of a bead coating via the Hamburg wheel tracking test and image analysis. METHODS : First, the stripping resistance of the bead coating was evaluated via the Hamburg wheel tracking test. A pneumatic wheel with a load of 175±2 N was used to simulate repeated skid cycles. Several bead coating mixtures with different numbers of coating layers, i.e., zero, one, two, three, and four layers, i.e., zero, one, two, three, and four layers,were conducted. Finally, an image analysis program was developed to analyze surface images captured from the Hamburg wheel tracking test. RESULTS : The results show that the samples with more coating layers exhibit higher stripping resistance. After 500 stripping cycles, the percentage of bead loss is 4% to 28%. At 80% bead loss, the mixture with one coating layer presents more skid cycles than the control sample without a coating layer. CONCLUSIONS : Incorporating a coating layer can improve the stripping resistance of glass beads under repeated skid cycles. Additionally, an image analysis program is established in this study to determine the percentage of bead loss caused by the stripping test.

PURPOSES : The aim of this study is to evaluate the effects of air voids, binder content, and aggregate gradation on the indirect tensile strength (IDT) and cracking tolerance index (CTindex) of cored asphalt pavements. METHODS : Cored samples were obtained from roads in Incheon city, and several laboratory experiments were performed. First, the cored samples were first to cut into a size appropriate for the IDT test. Subsequently, the air voids of the samples were measured. The damaged sample from the IDT test was loose mixed at 150 ℃ before the binder content was determined, which was conducted via an asphalt extraction test. Finally, the clean aggregates obtained from asphalt extraction process were analyzed in the aggregate gradation test. RESULTS : The result shows that an increase in air voids from 4% to 8% decreases the IDT and cracking tolerance index (CTindex) by 30% and 28%, respectively. Incorporating a binder enhances the ductile behavior of the asphalt mixture, resulting in a higher CTindex. Finally, the contribution of the aggregate grade on the IDT and CTindex is negligible. CONCLUSIONS : The IDT and CTindex are primarily affected by the air voids and binder content. A higher percentage of air voids results in a lower IDT. In addition, a higher amount of binder increases the IDT and CTindex of the cored samples. Meanwhile, the aggregate grade does not affect the IDT.

Putrescine은 일반적으로 미생물의 활동에 의해 발생되며, 신선함의 척도로서 사용된다. 그러나 동결건조된 로열젤리에 대한 putrescine 의 분석법은 아직 확립되지 않은 실정이다. 본 연구에서는 C18 컬럼을 이용하여 동결건조 로열젤리 내 putrescine을 분석하기 위한 UPLC 분석 법을 확립하고자 하였다. 새롭게 확립된 분석법은 7분 이내에 putrescine을 분석 가능하였으며, 이러한 분석법을 검증하기 위해 특이성, 직선성, 정밀성, 정확성, 정량한계, 정성한계 등을 평가하였다. 본 연구를 통해 동결건조 로열젤리의 신선한 정도를 평가하기 위한 분석법을 제공하였으 며, 추후 안전성의 척도에 대한 자료로서 활용 가능할 것으로 기대되어진다.

천적유지식물은 재배지에 천적을 지속적으로 유지할 수 있도록 하기 위하여 필요한 비작물성 식물이다. 미끌애꽃노린재는 총채벌레 등 원 예작물 해충의 주요 천적이지만, 재배지의 장기적인 유지를 위해서 효율적인 천적유지식물의 개발이 필요하다. 미끌애꽃노린재의 우수한 천적유 지식물을 선발하기 위하여 다양한 화밀식물 7종류(돌나물, 채송화 그리고 국화 5 품종)를 대상으로 미끌애꽃노린재의 산란율을 비교해 본 결과, 노란색 꽃을 가진 국화 품종에서 가장 높게 나타났다. 본 연구결과는 총채벌레 방제를 위한 미끌애꽃노린재의 효과를 증대하는데 기여할 것으로 판단된다.

The Cu2ZnSn(SxSe1-x)4 (CZTSSe) absorbers are promising thin film solar cells (TFSCs) materials, to replace existing Cu(In,Ga)Se2 (CIGS) and CdTe photovoltaic technology. However, the best reported efficiency for a CZTSSe device, of 13.6 %, is still too low for commercial use. Recently, partially replacing the Zn2+ element with a Cd2+element has attracting attention as one of the promising strategies for improving the photovoltaic characteristics of the CZTSSe TFSCs. Cd2+ elements are known to improve the grain size of the CZTSSe absorber thin films and improve optoelectronic properties by suppressing potential defects, causing short-circuit current (Jsc) loss. In this study, the structural, compositional, and morphological characteristics of CZTSSe and CZCTSSe thin films were investigated using X-ray diffraction (XRD), X-ray fluorescence spectrometer (XRF), and Field-emission scanning electron microscopy (FE-SEM), respectively. The FE-SEM images revealed that the grain size improved with increasing Cd2+ alloying in the CZTSSe thin films. Moreover, there was a slight decrease in small grain distribution as well as voids near the CZTSSe/Mo interface after Cd2+ alloying. The solar cells prepared using the most promising CZTSSe absorber thin films with Cd2+ alloying (8 min. 30 sec.) exhibited a power conversion efficiency (PCE) of 9.33 %, Jsc of 34.0 mA/cm2, and fill factor (FF) of 62.7 %, respectively.