PURPOSES : The purpose of this study is to identify the causes and expected problems of traffic flow in connection with ground roads that are expected to become stagnant owing to the increase in underground road infrastructure, and to derive methods to solve the problem in the future. METHODS : The basic design of underground roads is similar to that of tunnels. However, there is a point where the slope is large as the entering and exiting sections move underground. The ability of a heavy vehicle to assume a mound may vary depending on the slope. Therefore, in this study, a connection path section with a long slope was constructed using VISSIM, a simulation program, and it was verified whether analysis related to the slope and heavy vehicles in an underground road can be performed in the simulation. Subsequently, an analysis was conducted by setting a scenario and an effect index. In particular, this study analyzes internal delay patterns in the event of an unexpected situation on an underground connection road by performing shock wave analysis to analyze speed reduction according to heavy vehicles and slopes. RESULTS : A correlation between the slope of the underground road and decrease in the average speed according to the increasing rate of heavy vehicles was established. It was also possible to analyze the maximum length and duration of the delay connected to the rear in the event of a delay in the underground road and the shock wave speed transmitted to the rear. The analysis showed that the rate of increase in problems owing to delays ranged from 5% to 20% for the ratio of heavy vehicles. In particular, all effect scales increased significantly at a 9% slope. CONCLUSIONS : This study analyzes the causes of land congestion (slope and heavy vehicle mixing rate), which can be a major problem in underground roads in the future. In the future, by establishing lane-specific speed control strategies and lane control strategies based on this study, it will be necessary to derive solutions such as introducing traffic safety on the underground road by minimizing the shock wave delivered to the rear by providing information on traffic communication conditions inside the underground road to individual vehicles.

목적 : 본 연구는 안경광학과 재학생들의 안경사 윤리의식 인식정도를 파악하여 안경사로서의 윤리의식을 높일 수 있는 방안을 모색하고자 하였다. 방법 : 본 연구에서는 안경광학과 재학생 94명을 대상으로 직업윤리, 근로윤리 및 공동체윤리에 대한 인식도를 설문 조사하여 분석하였고, 각 항목 간의 상관관계는 Pearson 상관분석을 이용하였다. 결과 : 직업윤리에 대한 인식도 문항 중에서는 “직업의 의미를 설명할 수 있다”가 3.35±1.41점으로 가장 높은 점수를 보였다. 근로윤리에 대한 인식도 문항 중에서는 “정직의 의미를 설명할 수 있다”가 3.53±0.76점으로 가장 높은 점수를 보였다. 공동체윤리에 대한 인식도 문항 중에서는 “봉사의 의미를 설명할 수 있다”가 3.54±0.74점으 로 가장 높은 점수를 보였다. 직업윤리 인식도가 가장 높은 “직업의 의미를 설명할 수 있다”는 문항과 공동체윤리 인식도가 가장 높은 “봉사의 의미를 설명할 수 있다”는 문항 사이에는 양의 상관관계(r=0.52, p<0.001)가 나타났 다. 또한, 근로윤리 인식도가 가장 높은 “정직의 의미를 설명할 수 있다”는 문항과 공동체윤리 인식도가 가장 높은 “봉사의 의미를 설명할 수 있다”는 문항 사이에서도 양의 상관관계(r=0.72, p<0.001)가 나타났다. 결론 : 안경광학과 재학생들의 안경사 윤리의식 인식 정도가 타 직업군에 비해 낮게 나타났다. 따라서 졸업 후 임상에서 윤리적 책임을 완벽하게 수행하기 위해서는 세분화되고 체계적인 안경사 윤리교육의 내실화가 필요하다 고 생각된다.

With the mandatory implementation of ESC for trucks starting in 2023, domestic truck manufacturers in South Korea are advocating for a relaxation of the maximum safe slope angle to achieve cost savings. However, there is a lack of research on the dynamic safety of trucks based on ESC installation and the relaxation of the maximum safe slope angle. This study evaluates the relationship between static safety factor (SSF) and the maximum safe slope angle, analyzing the dynamic stability of trucks through simulation considering various experimental variables. The results quantitatively demonstrate the impact of relaxing the maximum safe slope angle on dynamic safety and provide recommendations for future safety regulations.

A typical trade-off relationship exists between strength and elongation in face-centered cubic metals. Studies have recently been conducted to enhance strength without ductility reduction through surface-treatment-based ultrasonic nanocrystalline surface modification (UNSM), which creates a gradient microstructure in which grains become smaller from the inside to the surface. The transformation-induced plasticity effect in Fe-Mn alloys results in excellent strength and ductility due to their high work-hardening rate. This rate is achieved through strain-induced martensitic transformation when an alloy is plastically deformed. In this study, Fe-6%Mn powders with different sizes were prepared by high-energy ball milling and sintered through spark plasma sintering to produce Fe-6%Mn samples. A gradient microstructure was obtained by stacking the different-sized powders to achieve similar effects as those derived from UNSM. A compressive test was performed to investigate the mechanical properties, including the yielding behavior. The deformed microstructure was observed through electron backscatter diffraction to determine the effects of gradient plastic deformation.

In this study, additive manufacturing of a functionally graded material (FGM) as an alternative to joining dissimilar metals is investigated using directed energy deposition (DED). FGM consists of five different layers, which are mixtures of austenitic stainless steel (type 316 L) and low-alloy steel (LAS, ferritic steel) at ratios of 100:0 (A layer), 75:25 (B layer), 50:50 (C layer), 25:75 (D layer), and 0:100 (E layer), respectively, in each deposition layer. The FGM samples are successfully fabricated without cracks or delamination using the DED method, and specimens are characterized using optical and scanning electron microscopy to monitor their microstructures. In layers C and D of the sample, the tensile strength is determined to be very high owing to the formation of ferrite and martensite structures. However, the elongation is high in layers A and B, which contain a large fraction of austenite.

Background: Lower back pain (LBP) is a major cause of disability and a common musculoskeletal disorder encountered at some point in life. Dysfunction of the lumbar vertebrae has been associated with decreased flexibility of the hamstrings, which exhibited a strong positive correlation with LBP. Hamstring tension affects lumbar pelvic rhythm. We aimed to activate pelvic stability with compression by Active Therapeutic Movement (ATM), muscle energy technique (MET) was applied to increase the flexibility of the hamstring. Objects: In this study, we aimed to investigate the effects of MET with ATM and general MET were applied to the hamstring of adults, who were in their twenties with nor without LBP, on their pelvic inclination and the length of their hamstring. Methods: A total of 32 subjects were briefed about the purpose of this study and agreed to participate voluntarily. Before the experiment, all subjects were pre-examined, and they were divided into an LBP group and a no lower back pain group accordingly. Thereafter, all subjects participated in both in a crossover manner. After at least one week, they switched to another group and participated in the same experiment. Results: The study results revealed that both groups demonstrated significant results in the modified active knee extension test (p < 0.01) and the sit and reach test (p < 0.01) performed to assess the hamstring flexibility; an interaction (p < 0.05) was noted. Moreover, a more significant difference was observed between the MET with ATM and the general MET. Although significant results were obtained for the pelvic inclination (p < 0.01), interaction was not noted. Conclusion: Conclusively, in this study, when the MET with ATM was applied to the two groups, there was a significant difference compared to the general MET for hamstring flexibility, but it was confirmed that there was no significant difference for the pelvic inclination.

최근 자기공명영상 획득을 위한 시뮬레이션 도구가 개발되어 오랜 시간이 소요되는 임상 연구를 대체할 수 있게 되었다. 이에 본 연구에서는 MRiLab 시뮬레이션을 사용하여 부가인자인 에코 시간의 변화에 따라 경사에코 펄스 시퀀스가 적용된 뇌 T2 강조 영상을 획득하여 영상의 신호 및 노이즈의 변화를 정량적으로 평가하고 경향성을 파악하고자 한다. 이를 위해 실제 MRI 장비를 기반으로 새롭게 개발된 MRiLab simulation tool을 사용하여 모든 파라미터를 같게 고정한 후 TE만을 20~95 ms범위에서 5 ms 간격으로 각각 설정하여 경사에코 펄스 시퀀스가 적용된 뇌 T2 강조 영상을 획득하였다. 획득된 영상들의 신호 및 노이즈 특성 변화를 정량적으로 평가하기 위해 신호대잡음비 및 대조대잡음비를 측정하였다. 결과적으로, TE가 증가할수록 SNR은 감소하고 CNR은 증가하는 경향을 보였다. 이는 TE가 증가할수록 관심 영역으로 설정된 뇌척 수액 신호는 일정하게 유지되는 반면 노이즈는 증가하였으며, 백그라운드로 설정된 백질의 경우 신호가 감소함과 동시에 노이즈가 증가한 것이 원인으로 분석된다. 결론적으로, 진단에 용이한 경사에코 펄스 시퀀스가 적용된 뇌 T2 강조 영상을 획득하기 위해서는 그 목적에 따라 적합한 TE를 설정하는 것이 중요함을 확인하였다.

본 연구의 목적은 골프 퍼팅 시 발생하는 운동학적 변인과 지면 경사도 인지능력 간 상관성을 분석하는 것이었다. 연구대상자는 신체 건강한 16명의 대학 골프선수들이 참여하였다. 퍼터 헤드의 운동학적 변인은 SAMPutt lab을 통해 분석하였다(70 Hz). 통계 분석은 Pearson 상관관계를 실시하였다. 평지 퍼팅 시 right 인지능력과 backswing 간 상관관계가 나타났다. 슬라이스 1° 퍼팅 시 toe-up 인지능력과 follow-through 간 상관관계가 나타났고, left 인지능력과 aim, backswing, impact, follow-through, loft 간 상관관계가 나타났다. 슬라이스 2° 퍼팅 시 toe-down 인지능력과 aim, backswing, impact 간 상관관계가 나타났다. 훅 2° 퍼팅 시 toe-up 인지능력과 follow-through 간 상관관계가 나타났다. 따라서 반복 적인 경사도 인지능력 훈련을 통해 퍼팅 스트로크를 개선시키는 골프 경기력 향상에 도움이 될 것으로 판단된다.

The research conducted on honorific and modest words is based on Chinese ancient books, records and handed-down documents. However, there is no consensus on research results due to various research materials used by scholars. This research employs Loulan Documents excavated during Wei-Jin period as research objects, and investigates the usage of honorific words and expressions and the phraseology of modest expressions. A quantity analysis based on thorough studies of most of the modest and honorific expressions in those documents was conducted. And, as a significant consequence, it is discovered that there is a slight usage difference between the honorific expressions in excavated documents during Wei-Jin period and in handed-down documents, which can be explained in three aspects. First of all, the second personal pronouns ‘er’ and ’ru’ are not unseemly words, and ‘er’, ‘ru’ and ‘jun’ are most widely used. Secondly, although part of the frequently used honorific expressions in later ages are used to express modest and respect in Wei-Jin period, they are not grammaticalized and cannot be considered as actual honorific expressions. Thirdly, during Wei-Jin period, not only there are honorific words and expressions, there are also fixed formats of expressing modesty.

This study discussed the effects of inclined interface location to apply the design of inclined interface of composite materials subjected to shear loading. The fracture parameters are analyzed by finite element method of ANSYS. As a results, If in case of the angle of inclination is 45 degrees, inclined interface is longer and the crack tip is closer, the less the crack suppression effect. If the inclined interface location is a more than twice the length of the inclined interface, the effect of suppressing crack propagation are constant regardless of the location. In case of the inclined interface is longer and the crack tip is closer, the cause of increase of energy release rate is a due to the increase of shear stress. If in case of the angle of inclination is 90 degrees, inclined interface is closer to the crack tip, the better the crack suppression effect. If the inclined interface location is a less than twice the length of the inclined interface, the effect of suppressing crack propagation are dominant. And if the inclined interface location is a more than twice the length of the inclined interface, crack suppression effect is gradually reduced.

Background: In previous studies, changes in postural alignment were found when the slope was changed during walking. Downhill walking straightens the trunk by shifting the line of gravity backward. Objects: This study investigated the effect of the downhill treadmill walking exercise (DTWE) on thoracic angle and thoracic erector spinae (TES) activation in subjects with thoracic kyphosis. Methods: A total of 20 subjects with thoracic kyphosis were recruited for this study. All the subjects performed the DTWE for 30 minutes. A surface EMG and 3D motion capture system were used to measure TES activation and thoracic angle before and after the DTWE. Paired t-tests were used to confirm the effect of the DTWE (p<.05). Results: Both the thoracic angle and TES activation had significantly increased after the DTWE compared to the baseline (p<.05). An increase in the thoracic angle indicates a decrease in kyphosis. Conclusion: The DTWE is effective for thoracic kyphosis patients as it decreases their kyphotic posture and increases the TES activation. Future longitudinal studies are required to investigate the long-term effects of the DTWE.