역학적 파동을 이용한 콘크리트 흄관의 내부 수직 균열 탐사 시스템

강상구 대한건축학회지회연합회 2023 대한건축학회연합논문집 Vol.25 No.2

Concrete cracks are early indicators of material performance degradation and defects, and concrete crack monitoring is an important technique that helps to reduce maintenance costs and improve the performance and safety of concrete structures. Existing techniques, including visual inspection, are based on the surface crack images or ultrasonic velocity differences and have limitations to find internal cracks (e.g., concrete delamination and flexural cracks). Therefore, in this study, a detection system was developed using wave attenuation of guided waves for detecting concrete internal cracks. The system was verified through finite element analysis and crack exploration experiments in concrete hume pipes. The surface cracks showed more wave energy attenuation than the internal cracks since the surface waves transmit higher energy than the body waves resulting in more energy reflection and scattering. On the other hand, in the case of internal cracks. As a result, it showed sufficient sensitivity to detect both surface and internal cracks and can be developed into a crack evaluation system with a damage index in the future.

분산에너지시대 개막, 지자체의 역할 및 기대 : 분산에너지활성화특별법, 내년 6월 시행

강상구,강영심,이용희,이한우,이훈 대한전기협회 2023 전기저널 Vol.- No.560

Cs-137 감마선 조사실의 차폐벽에 의한 산란선 영향 연구

강상구,노성진,김현,김효진,정동혁,강영록 대한방사선방어학회 2016 대한방사선방어학회 학술발표회 논문요약집 Vol.2016 No.12

The Impact of Household Economic Deterioration Caused by the COVID-19 Pandemic and Socioeconomic Status on Suicidal Behaviors in Adolescents: A Cross-sectional Study Using 2020 Korea Youth Risk Behavior Web-based Survey Data

강상구,Yeri Jeong,Eun Hye Park,Seung-sik Hwang 대한예방의학회 2022 예방의학회지 Vol.55 No.5

Objectives: Economic hardship has a serious impact on adolescents’ mental health. The financial impact of the coronavirus disease 2019 (COVID-19) pandemic was more severe for low-income families, and this also impacted adolescents. This study aimed to examine the associations of economic deterioration (ED) caused by the COVID-19 pandemic and low socioeconomic status (SES) with adolescents’ suicidal behaviors. Methods: This study analyzed data from the 2020 Korea Youth Risk Behavior Web-based Survey, which included 54 948 middle and high school students. Odds ratios (ORs) of suicidal ideation, suicidal planning, and suicide attempts related to ED and SES were calculated using multivariable logistic regression. We calculated relative excess risks due to interaction to assess additive interactions. Results: The ORs for suicidal ideation, suicidal planning, and suicide attempts related to combined severe ED and low SES were 3.64 (95% confidence interval [CI], 3.13 to 4.23), 3.88 (95% CI, 3.09 to 4.88), and 4.27 (95% CI, 3.21 to 5.69), respectively. Conclusions: ED and low SES were significantly associated with suicidal behaviors in adolescents. Although no significant additive interaction was found, the ORs related to suicidal ideation, suicidal planning, and suicide attempts were highest among adolescents from low-income families with severe ED. Special attention is needed for this group, considering the increased impact of economic inequality due to the COVID-19 pandemic.

비간섭산란파를 이용한 섬유보강 콘크리트의 초기 균질성 평가

강상구,최민우,최열 대한건축학회지회연합회 2023 대한건축학회연합논문집 Vol.25 No.3

This study performed to quantify material homogeneity in order to evaluate the properties of concrete by conducting ultrasonic pulse experiments and developing/applying homogeneity index algorithm. Parameters that can affect the homogeneity evaluation are recognized, and the homogeneity variation according to the influencing factors is investigated. In addition, the homogeneity variation according to compressive strength and age is calculated to check the material homogeneity sensitivity in the case of plain concrete and fiber-reinforced concrete. The experimental results of steel fiber reinforced concrete show that the calculated homogeneity is proportional to the compressive strength and age. In addition, the surface treatment of concrete for compressive strength measurement affects the homogeneity, and the moisture content also affects the homogeneity. These relationships can be clarified in future studies by conducting experimental and analytical studies considering various variables. 본 연구는 화합물로써의 콘크리트의 특성을 평가하기 위하여 재료 균질성을 수치화하는 것을 목표로 초음파 펄스 실험을 실시하고 균질도 산출 알고리즘을 개발/적용하고자 하였다. 균질성 평가에 영향을 미칠 수 있는 요소들을 인지하고, 영향인자에 따른 균질도 변화를 확인하였다. 또, 압축강도와 재령에 따른 균질도 변화를 산출 함으로써 일반 콘크리트와 섬유보강 콘크리트 각각의 경우 재료 균질성 민감도를 확인하였다. 강섬유를 보강한 콘크리트의 실험적 연구 결과는 산출된 균질도가 압축강도와 재령에 비례하는 것으로 나타났다. 또, 압축강도 측정을 위한 콘크리트 면처리가 균질도에 영향을 미치며, 수분 함유량 또한 균질도에 영향을 미치는 것으로 나타났다. 이는 향후 연구에서 다양한 변수를 고려한 실험적 해석적 연구를 통해 관계가 규명 될 수 있다.

중복 설치된 지적기준점·국가기준점의 효율적인 정비 방안

강상구,이영진,차득기 한국국토정보공사 2010 지적과 국토정보 Vol.40 No.1

In order to effectively integrate the different types of the control points, this project has intensively derived a series of standard procedures: (a) criterion for determining the overlapped-setup points; (b) criterion for abrogating control points which have large discrepancy; (c) integration procedure of national survey control points; (d) field observation procedure. In overlapped-setup points rearrangement, it is suggested from the investigation that the cadastral control points should be maintained in rearrangement of the overlapped-setup points. This is mainly due to the fact that the cadastral points have much implication to public users. However, investigation should systematically be carried out to study the linkage with the surrounding cadastral control points, the relationship with other control points, the applied range of results in advance. Furthermore, it is proposed that coordinate system being maintained, as schemes for joint use of rearranged cadastral points and for linking with the excited coordinates. Hence, the published coordinates of all the cadastral control points is able to be transformed into the global coordinate system. 국가기준점을 하나로 통합하기 위해 중복기준점의 판정기준, 통합방법과 절차, 성과산출 방안, 폐기방법 등을 체계적으로 정립하고 시험관측 계획을 수립하였으며, 통과성과의 산정방안과 문제점에 대한 분석 및 활용방안을 고찰하였다. 중복 설치된 기준점 정비는 국가기준점에 비하여 지적기준점의 경우가 파급효과가 크기 때문에 물리적인 폐기보다는 주변 지적기준점과의 연계성, 다른 기준점과의 관계와 활용성, 성과가 이용된 범위, 이력 등을 체계적으로 조사하는 과정이 선행되어야 할 것으로 판단된다. 또한 정비된 지적기준점을 공동 활용하고 종전 성과와의 연계를 위한 방안으로는 현행체계를 유지하면서 점진적으로 세계측지계로 통합하거나 모든 지적기준점 성과를 세계측지계로 전면 전환하는 방안을 제시하였다.

Student Performance and Satisfaction in Online vs. Offline English Course: Do Delivery and Exam Format Matter?

강상구 현대영어교육학회 2021 현대영어교육 Vol.22 No.2

The COVID-19 pandemic forced educational institutions around the world to suddenly shift most of their traditional offline classes to the online in 2020. Korean universities were no exception to the trend, and it provided an opportunity to investigate student performance and satisfaction in an online versus offline university English course. In this study, an introductory English linguistics course conducted online in 2020 was compared to the same course conducted offline in 2019. The exams of the online English class probed in this study were the same versions used for the offline class consisting of multiple choice and short answer questions, but were administered in an openbook online format without a proctor. Then, students’ course evaluation results were analyzed to compare their satisfaction in different class delivery formats. Results of online and offline classes revealed that students’ exam results and course evaluation were almost identical, which suggest that the online format of university courses can be as effective as the traditional offline courses for the recent younger generation of online-friendly university students.

Seeking to Relieve Demotivation for Korean College Students Learning English

강상구 범태평양 응용언어학회 2019 범태평양응용언어학회지 Vol.23 No.2

Demotivation is a relatively new and trending topic in the field of L2 learning. Previous studies have attempted to classify several factors related to demotivation and identify how those factors affect teachers and L2 learners. In the current study, a short questionnaire with items that can be classified into five demotivation factors based on findings from previous research ((a) Learning Contents & Materials, (b) Teachers’ Competence & Teaching Styles, (c) Lack of Intrinsic Motivation, (d) Test Score, and (e) Peer Environment) was completed by 40 students at the end of a college English reading class. One of the goals is to probe how these demotivation factors affect students with different achievement levels. The results demonstrated that three of the factors (Teachers’ Competence & Teaching Styles, Lack of Intrinsic Motivation, and Peer Environment) did not function as high demotivation factors, while the other two (Learning Contents & Materials and Test Score) were demotivating for low achievement level students. These results suggest that factors related to teachers, students, and fellow students were not demotivating while the textbook and scoring system were discouraging students in this course. Another important goal of this study is to propose how demotivation might be relieved in the classroom, especially related to test scores. After all, the ultimate goal of studying demotivation would be to eliminate it in order to maximize learning. With that in mind, it may be time to consider an alternative method of evaluating students in the classroom. Instead of maintaining the current practice of setting a fixed proportion of students who are allowed to receive good grades, an alternative could be introduced. For example, a credential-type acknowledgement based on the competency that the students achieve should be considered.

화상 반흔에서 생긴 궤양을 동반한 이소성 석회화의 치료

강상구,이종욱,고장휴,서동국,최재구,장영철,Kang, Sang-Gu,Lee, Jong-Wook,Ko, Jang-Hyu,Seo, Dong-Kook,Choi, Jai-Koo,Jang, Young-Chul 대한성형외과학회 2010 Archives of Plastic Surgery Vol.37 No.4

Purpose: Heterotopic calcification is a pathological event in which deposits of calcium salts build up, usually in the joint area or soft tissues. It can occur under many conditions and in some rare cases may develop in burn scars. In particular, ulcerations in burn scars accompanied by heterotopic calcification are difficult to treat through conservative treatment. This study reports methods for accurate diagnosis and adequate treatment of ulceration in burn scars accompanied by heterotopic calcification. Methods: Fourteen patients who visited our hospital from March 2008 to January 2010 were subjected to this study. Their sex, age, modes of burn, degree, TBSA (%), ulcerated area, the time of occurrence of the ulcerations in the burn scars were investigated. In addition, radiological examination and biopsy was performed to diagnose heterotopic calcification. Results: Among the 14 cases, 6 were male and 8 were female. The average age of the patients was 48.2 (27 - 69 yrs). As for the mode of burn, 11 were flame burns and 3 were scalding burns. The average time of occurrence of the ulcerations in the burn scars was 4.5 months. The ulcerated areas were situated in the legs in 12 cases, arms in 1 case, and torso in 1 case. The diagnosis was confirmed through X-ray and biopsy, and skin graft was performed after wide excision. Conclusion: Diagnosis of the ulceration in burn scars accompanied by heterotopic calcification is possible through radiological and pathologic studies. Surgical treatment is the most reliable method of treatment, and we chose to perform skin graft after wide excision. Also, we learned that the complete removal of the calcified tissue and the inflammatory fibrotic tissues is crucial in preventing recurrence. Also, in contrast to Marjolin's ulcer, heterotopic calcification had a small size, little or no granulation tissue, and lacked fungating type ulceration. Therefore, favorable prognosis could be achieved through adequate treatment.

Indentification of Differentially Displayed Genes of a Pseudomonas Resistant Soybean(Glycine max)

강상구,박의호,장무웅,HyeonWookCha 한국식물병리학회 2003 Plant Pathology Journal Vol.19 No.5

In Korea, a local soybean (Glycine max) genotype 561 was found to be strongly resistant to a virulent bacterial strain of a Pseudomonas sp. SN239. Specific genes involved in the resistance of the soybean genotype 561 were identified and the pattern of gene expression against the Pseudomonas infection was analyzed using differential-display reverse transcription PCR (DDRTPCR). More than 126 cDNA fragments representing mRNAs were induced within 48 hours of bacteria inoculation. Among them, 28 cDNA fragments were cloned and sequenced. Twelve differentially displayed clones with open reading frames had unknown functions. Sixteen selected cDNA clones were homologous to known genes of other organisms. Some of the identified cDNAs were pathogenesis-related (PR) genes and PRlike genes. These cDNAs included a putative calmodulinbinding protein; an endo-1,3-1,4-β-D-glucanase; a β- 1,3-endoglucanase; a β-1,3-exoglucanase; a phytochelatin synthetase-like gene; a thiol protease; a cycloartenol synthase; and a putative receptor-like serine/threonine protein kinase. Among them, four genes were found to be putative PR genes induced significantly by the Pseudomonas infection. These included a calmodulinbinding protein gene, a β-1,3-endoglucanase gene, a receptor-like serine/threonine protein kinase gene, and pS321 (unknown function). These results suggest that the differentially expressed genes may mediate the strong resistance of soybean 561 to the strain SN239 of Pseudomonas sp.