The Effect of Train Acceleration on the Pantograph Dynamics

Kim, Jung Soo Research Institute of Science and Technology HONGI 2005 Hongik Journal of Science and Technology Vol.9 No.-

The dynamic characteristics of the pantograph are evaluated by conducting a test run in which signals from accelerometers and load cells attached to the various parts of the pantograph assembly are evaluated. By analyzing these signals, it has been found that the dynamic characteristics of the pantograph are strongly influenced by the train speed, with the major frequency components arising from the train traversing the span spacing and the 8.5 Hz component originating from the panhead resonance. The train acceleration is found to have significant influence on the span passing frequency but negligible effect on the resonant response.

Cardinal Andrew YEOM Soo-jung

YEOM Soo-jung 신학과사상학회 2018 가톨릭 신학과 사상 Vol.- No.81

김정일 시대 북한의 대남기동성 정치에 관한 유형화 연구

정현수(Hyun-Soo Jung) 경희대학교 인류사회재건연구원 2017 OUGHTOPIA Vol.32 No.2

김정일 집권기간 동안의 북한이 핵역량을 강화하려는 시도는 국제관계에서 약소국이 강대국을 상대로 외교적 영향력을 행사하면서 국가이익을 확보하는 약소국의 외교적 기동성에 해당한다. 김정일 시대에서 한미동맹은 협력과 갈등을 반복하면서 북한의 대남기동성에도 결정적인 영향을 미친 것으로 분석되었다. 분석에 따르면, 김영삼 정부가 선택한 대북 강경노선은 한미갈등을 유발하고 북한이 ‘통미봉남’ 전략을 구사하면서 저항형 배제를 통해 기동성을 발휘하였고, 대북온건노선을 선택한 김대중 정부에 대해서는 미국의 정권교체에 동반된 한미동맹과의 협력과 갈등에도 불구하고 순응형 협력행태를 통해 실리추구형 대남기동성을 확보할 수 있었다. 그러나 대북 온건노선을 주장한 노무현 정부에 대해서는 한미갈등을 기반으로 순응하면서도 저항하는 병행적 순응형으로 기동성을 발휘한 것으로 분석되었다. 그리고 마지막으로 이명박 정부에 대해서는 대북압박공조에 대응하여 적대적 맞대응전략을 구사하면서 위협과 다변화를 통해 대남 기동성을 확보하는데 성공할 수 있었다. 이상의 내용을 토대로 김정일 시대에서 북한의 대남기동성은 북한의 외교적 역량의 산물보다는 한미동맹에 기반하고 있는 분단체제의 복합적 구조의 산물로 볼 수 있다는 결론에 도달하였다. North Korea exercised its maneuverability against South Korea during Kim Jung-il’s regime by having aligned with an adversarial power through ‘bandwagoning’ and exerted influence accordingly. From this, it can be noticed that North Korea’s maneuverability against South Korea took different forms according to changes of ROK-US alliance. Kim Jung-il pursued a policy of dialogue toward the US but isolation toward South Korea and excluded the resistant power during Kim Young-sam government. During Kim Dae-jung government, North Korea demonstrated ‘compliance cooperation.’ During Roh Moo-hyun government, North Korea took a multilateral approach. Lastly, during Lee Myung-bak government, North Korea successfully acquired its maneuverability against South Korea through ‘resistance escalation’. Thus, ROK-US alliance has been identified as a crucial factor that affects North Korea’s maneuverability against South Korea.

학교 부적응 청소년을 위한 승마 여가교육 프로그램 개발 및 효과 검증

박수정(Park, Soo-Jung),김민규(Kim, Min-Kyu) 한국사회체육학회 2015 한국사회체육학회지 Vol.0 No.62

This study aims to develop a program on horse riding leisure education for school maladjusted adolescents. To this end, a program on horse riding leisure education was developed based on structuring factor drawn from the study of Park, Soo-Jung and Kim, Min-Kyu(2014) on horse riding leisure education for school maladjusted adolescents and then, the content validity was verified by an expert group. In addition, developed program of horse riding leisure education was applied to 6 school maladjusted adolescents to verify the program validity. Through such process, total 16 sessions of horse riding leisure education program were developed including 5 programs of horse stable activity region, 3 programs of horseback activity region, and 8 programs of horse riding leisure education and counseling region. Verification of the content validity by a expert group showed that validity was ensured. According to the application of horse riding leisure education program to 6 school maladjusted students and the inductive classification of category through in-depth interview, it was revealed that the program had positive influence on school maladjusted students by improvement of interpersonal relations, recognition of the sanctity of life, improvement of consideration and endurance, improvement of confidence, and stress reduction.

한국인 직무 스트레스 측정도구의 개발 및 표준화

장세진,고상백,강동묵,김성아,강명근,이철갑,정진주,조정진,손미아,채창호,김정원,김정일,김형수,노상철,박재범,우종민,김수영,김정연,하미나,박정선,이경용,김형렬,공정옥,김인아,김정수,박준호,현숙정,손동국 大韓産業醫學會 2005 대한직업환경의학회지 Vol.17 No.4

Background and Purposes: Over the past three decades, numerous studies performed in Korea have reported that job stress is a determinant risk factor for chronic diseases and work disability. Every society has its own culture and occupational climate particular to their organizations, and hence experiences different occupational stress. An occupational stress measurement tool therefore needs to be developed to estimate it objectively. The purpose of this study is to develop and standardize the Korean Occupational Stress Scale (KOSS) which is considered to be unique and specific occupational stressors in Korean employees. Subjects and Methods: Data were obtained from the National Study for Development and Standardization of Occupational Stress (NSDSOS Project: 2002-2004). A total of 12,631 employees from a nationwide sample proportional to the Korean Standard Industrial Classification and the Korean Standard Occupational Classification were administered. The KOSS was developed for 2 years (2002-2004). In the first year, we collected 255 items from the most popular job stress measurement tools such as JCQ, ERI, NIOSH and OSI, and 44 items derived from the a qualitative study (depth interview). Forty-three items of KOSS, in the second year, were retained for use in the final version of the KOSS by using Delphi and factor analysis. Items were scored using conventional 1-2-3-4 Likert scores for the response categories. Results: We developed eight subscales by using factor analysis and validation process: physical environment (3 items), job demand (8 items), insufficient job control (5 items), interpersonal conflict (4 items), job insecurity (6 items), organizational system (7 items), lack of reward (6 items), and occupational climate (4 items). Together they explained 50.0% of total variance. Internal consistency alpha scores were ranged from 0.51 to 0.82. Twenty-four items of the short form of the KOSS (KOSS-SF) were also developed to estimate job stress in the work setting. Because the levels of the subscales of occupational stress were gender dependent, gender-specific standard norms for both the 43-item full version and the 24-item short form using a quartile for the subscales of KOSS were presented. Conclusion: The results of this study suggest that KOSS might be an appropriate measurement scale to estimate occupational stress of Korean employees. Further and more detailed study needs to be conducted to improve the validity of this scale.

Microstructure‑Strengthening Interrelationship of an Ultrasonically Treated Hypereutectic Al–Si (A390) Alloy

Soo‑Bae Kim,Young‑Hee Cho,Jae‑Gil Jung,Woon‑Ha Yoon,Young‑Kook Lee,Jung‑Moo Lee 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.6

Ultrasonic melt treatment (UST) was applied to an A390 hypereutectic Al–Si alloy in a temperature range of 750–800 °Cand its influence on the solidification structure and the consequent increase in strength was investigated. UST at such a hightemperature, which is about 100 °C above the liquidus temperature, had little effect on the grain refinement but enhanced thehomogeneity of the microstructure with the uniform distribution of constituent phases (e.g. primary Si, α-Al and intermetallics)significantly refined. With the microstructural homogeneity, quantitative analysis confirmed that UST was found tosuppress the formation of Cu-bearing phases, i.e., Q-Al5Cu2Mg8Si6, Al2Cuphases that form in the final stage of solidificationwhile notably increasing the average Cu contents in the matrix from 1.29 to 2.06 wt%. A tensile test exhibits an increasein the yield strength of the as-cast alloy from 185 to 208 MPa, which is mainly associated with the solute increment withinthe matrix. The important role of UST in the microstructure evolution during solidification is discussed and the mechanismcovering the microstructure-strengthening interrelationship of the ultrasonically treated A390 alloy is proposed.

반복적인 실신 및 실신전환자의 기립경사 검사시 뇌혈류 변화

조수진,김준수,이광호,정진상,송희정,이상철,서정돈,이원로 대한신경과학회 1999 대한신경과학회지 Vol.17 No.3

CONVERGENCE OF APPROXIMATING FIXED POINTS FOR MULTIVALUED NONSELF-MAPPINGS IN BANACH SPACES

Jung, Jong Soo The Kangwon-Kyungki Mathematical Society 2008 한국수학논문집 Vol.16 No.2

Let E be a uniformly convex Banach space with a uniformly $G{\hat{a}}teaux$ differentiable norm, C a nonempty closed convex subset of E, and $T:C{\rightarrow}{\mathcal{K}}(E)$ a multivalued nonself-mapping such that $P_T$ is nonexpansive, where $P_T(x)=\{u_x{\in}Tx:{\parallel}x-u_x{\parallel}=d(x,Tx)\}$. For $f:C{\rightarrow}C$ a contraction and $t{\in}(0,1)$, let $x_t$ be a fixed point of a contraction $S_t:C{\rightarrow}{\mathcal{K}}(E)$, defined by $S_tx:=tP_T(x)+(1-t)f(x)$, $x{\in}C$. It is proved that if C is a nonexpansive retract of E and $\{x_t\}$ is bounded, then the strong ${\lim}_{t{\rightarrow}1}x_t$ exists and belongs to the fixed point set of T. Moreover, we study the strong convergence of $\{x_t\}$ with the weak inwardness condition on T in a reflexive Banach space with a uniformly $G{\hat{a}}teaux$ differentiable norm. Our results provide a partial answer to Jung's question.

Periapical multilocular osteoporotic bone marrow defect

Jung, Yun-Hoa,Cho, Bong-Hae,Nah, Kyung-Soo 대한구강악안면방사선학회 2005 Imaging Science in Dentistry Vol.35 No.4

A case of osteoporotic bone marrow defect, which appeared as a well-defined multilocular radiolucency overlapping the roots of mandibular right second molar, was reported. On periapical radiograph, a daughter cyst-like radiolucency was seen at the anterior margin of the lesion making it difficult to rule out odontogenic keratocyst.

Effect of Ultrasonic Melt Treatment on Solidification Microstructure of Al–5Ti–1B Alloy Containing Numerous Inoculant Particles

Soo‑Bae Kim,Jae‑Gil Jung,Young‑Hee Cho,Su‑Hyeon Kim,Kwangjun Euh,Jung‑Moo Lee 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.7

The effect of ultrasonic melt treatment (UST) on the solidification microstructure of an Al–5Ti–1B alloy containing highvolumefractions of Al3Tiand TiB2particles is investigated for various UST times with different melt holding times. Theas-cast Al–5Ti–1B alloy is composed of TiB2and polygonal Al3Tiparticles (present prior to UST), plate-like Al3Tiparticles,and Al grains (formed during UST and/or solidification). The UST causes a size reduction and homogeneous distributionof the TiB2-agglomerated region containing many submicron-sized TiB2particles pushed to the grain boundaries. The USTslightly decreases the size and improves the distribution of polygonal Al3Tiparticles enriched in the TiB2-agglomeratedregion. Unlike the TiB2and polygonal Al3Tiparticles, which exhibit a minor refining effect, the plate-like Al3Tiparticlesshow a significant refinement with UST application. The UST has a significant effect on the size distribution of Al grains byinducing the formation of medium-sized grains at the expense of small and large grains; however, it only has a slight effecton grain refinement. The degree of microstructure modification increases with increasing UST time but decreases with meltholding time after UST. The mechanisms for the refinement and dispersion of the TiB2and Al3Tiparticles and Al grains arediscussed considering fragmentation, nucleation, and growth behaviors induced by the UST and subsequent solidification.