금속 벌크소재의 성형한계 정의를 위한 삼축응력선도 도출 연구

서영호 한국기계기술학회 2020 한국기계기술학회지 Vol.22 No.5

The method of evaluating the forming limit of sheet metal is using the forming limit diagram(FLD), and the test method for measuring forming limit curve(FLC) is ISO standardized. On the other hand, in the case of metal bulk materials, it was confirmed that the forming limit was defined by using various predictive models based on the ductile fracture theory. However it did not show a constant forming limit (limit damage value) depending on the shape of the specimen. Therefore, a study was conducted on the derivation of the triaxial stress curve to predict the fracture of the material for various stress triaxiality, not the existing limit damage value.

Alleviating Effect of Salicylic Acid Pre-treatment on Soil Moisture Stress of Waxy Corn

서영호,류시환,박종열,최재근,박기진,김경희 한국토양비료학회 2015 한국토양비료학회지 Vol.48 No.3

Soil moisture shortage can reduce yield of waxy corn because maize is one of the sensitive crops to the drought stress. Farmers cannot irrigate due to limited water resource and irrigating facilities although applying water is the most effective practice to solve the drought problem. The study was conducted to investigate the pre-treatment effect of salicylic acid on reducing drought damage of waxy corn (Zea mays L.). Salicylic acid at concentration of 0.2 mM was applied at seven-leaf stage or ten-leaf stage three times. Drought stress was imposed by withholding irrigation from 11 days before anthesis to 10 days after anthesis. Application of salicylic acid significantly increased ear length by 11.0~12.3% and yield by 8.8~11.3% compared with non-treated control, indicating that the drought injuries of waxy corn can be alleviated through pre-treatment of salicylic acid at the vegetative stage.

Nitrous Oxide Emissions from Red Pepper, Chinese Cabbage, and Potato Fields in Gangwon-do, Korea

서영호,김근엽,박기진,김경희,정영상 한국토양비료학회 2013 한국토양비료학회지 Vol.46 No.6

The level of nitrous oxide (N2O), a long-lived greenhouse gas, in atmosphere has increased mainly due toanthropogenic source, especially application of nitrogen fertilizers. Quantifying N2O emission fromagricultural field is essential to develop national inventories of greenhouse gases (GHGs) emission. Theobjective of the study was to develop emission factor to estimate direct N2O emission from agricultural fieldin Gangwon-do, Korea by measuring N2O emissions from potato (Solanum tuberosum), red pepper (Capsicumannum L.), and Chinese cabbage (Brassica campestris L.) cultivation lands from 2009 to 2012. AccumulatedN2O emission was 1.48±0.25 kg N2O-N ha-1 for red pepper, 1.27±0.27 kg N2O-N ha-1 for potato, 1.49±0.06 kgN2O-N ha-1 for Chinese cabbage cultivated in spring, and 1.14±0.22 kg N2O-N ha-1 for fall Chinese cabbage. Emission factor of N2O calculated from accumulated N2O emission, nitrogen fertilization rate, and backgroundN2O emission was 0.0051±0.0016 kg N2O-N kg-1 N for cropland in Gangwon province. More extensive studyis deserved to be conducted to develop N2O emission factor for upland crops in Korea through examining theemission factors from various regions and crops because N2O emission is influenced by many factorsincluding climate characteristics, soil properties, and agricultural practices.

“기업가치 성장과 재무자산의 관점에서 바라본 4차 산업혁명 파급 효과” 에 대한 실증 연구논문 (제조기업에서의 지식 가치 창출 활동 및 재무정보의 시계열 변화 중심으로)

서영호,배기수 한국창업학회 2023 한국창업학회지 Vol.18 No.1

The European Patent Office Secretariat (EPO) analyzed the global patent database in time series and defined 2010 as the time when the 4th industrial revolution technology began to spread rapidly. Through this study, it was demonstrated from the perspective of knowledge value creation activities and financial information that "whether the fourth industrial revolution technology has a practical ripple effect throughout the manufacturing sector from 2010". This study examined the level of influence of knowledge assets for the corporate value growth& management performance before and after the 4th industrial revolution, focusing on time series in terms of the relationship with the corporate growth & financial factor /asset structure. From 1980 to 2020, the level of intellectual property creation activities and financial information of KOSPI/KOSDAC listed manufacturers were collected quantitatively. The collected data were divided into two groups before and after the 4th Industrial Revolution (as of 2010year). For each group, the level of knowedge value creation activies(intellectual property), asset level, and asset structure's impact on corporate value growth(market capitalization)& management performance(net profit) were quantitatively analyzed based on statistical processing. By deriving correlation and polynomial regression equations for each group and comparing them between the two groups, we could quantitatively grasp the type of change in the regression model and the financial factors that is significantly affected the corporate growth value after the 4th Industrial Revolution. The degree to which knowledge value creation activities contributes to corporate value growth (market capitalization) and management performance (net income) increased further after the 4th Industrial Revolution, and in particular, knowledge value creation actitvities showed a clear increase in corporate value growth (market capitalization) rather than management performance (net income). Based on the European Patent Office's study for patent DB that is 4th Industrial Revolution technology, it is possible to clarify the spread timing of the 4th Industrial Revolution technology from the perspective of corporate value growth and financial assets. And also, this study is helpful in quantitatively studying the corporate value growth model reflecting financial factors linked to the increasing trend of knowledge value creation activities in the era of the 4th industrial revolution. 유럽 특허 사무국(EPO)에서는 글로벌 특허 데이터베이스를 시계열 분석하여, 4차 산업혁명 기술이 확산된 시점을 2010년 이후로 정의하였고, 본 연구를 통하여 “2010년부터 4차 산업혁명 기술이 제조 분야 전반에 실질적인 파급 효과를 내고 있는지”를 지식 가치 창출 활동과 재무 정보의 관점에서 실증하였다. 본 연구에서는 4차 산업혁명을 전후하여 지식 가치 창출 활동이 기업가치 성장 및 경영성과에 미친 영향력의 수준을 재무요소/자산구조와의 관계 측면에서 시계열 중심으로 살펴보았다. 1980년부터 2020년에 이르기까지 국내 상장 제조기업이 가지는 지식 가치 창출 활동 수준과 재무정보를 정량적으로 수집하였다. 수집된 데이터를 2010년을 경계로 4차 산업혁명 전/후 두 그룹으로 나누고, 각 그룹에 대해, 지식 가치 창출 수준 및 강도, 자산 수준, 자산 구조가 기업가치 성장 및 경영성과에 어떻게 영향을 미쳤는지의 상관관계를 분석하고, 다항 회귀식을 각 그룹 별로 도출하여, 전/후 두 그룹 간에 비교함으로써, 4차 산업혁명 기술이 급격히 확산된 2010년 이후의 회귀모델의 변화 형태와 기업가치에 유의한 영향을 준 재무요인의 영향력 변화 수준을 정량적으로 파악할 수 있었다. 지식 가치 창출 활동 수준이 기업가치 성장과 경영성과에 기여하는 정도가 4차 산업혁명 기술 확산된 시기 (2010년) 이후에는 더욱 증가하였고, 특히 지식 가치 창출 활동 수준 (지식자산)은 경영 성과(당기순이익)보다 기업가치 성장(시가총액)에 뚜렷한 증가를 나타냈다. 4차 산업혁명 기술의 확산 시점에 대한 유럽 특허청의 특허 DB 분석 결과를 기반으로 하여, 지식 가치 창출 활동을 기업가치 성장과 재무자산의 관점에서 실증함으로써, 4차 산업혁명 기술이 산업 전반으로 확산된 시점(2010년)을 실증적으로 규명해볼 수 있었고, 4차 산업혁명 시대에 지식 가치 창출 활동 증가 추세와 연동된 재무 인자들을 반영한 기업가치 성장 모델을 정량화하는 시도에 본 연구가 도움이 되기를 기대한다.

웨이블릿 영역의 부대역 상관도를 이용한 디지털 영상 워터마킹

徐英鎬,朴鎭永,金東郁 대한전자공학회 2003 電子工學會論文誌-SP (Signal processing) Vol.40 No.11

The watermarking is the technique that embeds or extracts the certain data without the change of the original data for the copyright protection of the multimedia contents. Watermark-embedded contents must not be distinguished by human's eye and must be robust to the various image processing and the intentional distortions. In this paper, we propose a new watermarking technique applied in the wavelet domain which has both the spatial and frequency information of a image. For both the robustness and the invisibility, the positions for embedding the watermark is selected with the multi-threshold. We search the similarity between highly correlated coefficients in the each subband and decide the mark space after verifying the significance in the specified subband. The similarity is represented by the coefficient difference between the subbands and its distribution is used in the watermark embedding and extracting. The embedded watermark can be extracted without the original image using the relationship of the subbands. By these properties the proposed watermarking algorithm has the invisibility and the robustness to the attacks such as JPEG compression and the general image processing. 워터마킹(Watermarking) 기법은 멀티미디어 컨텐츠의 저작권 보호를 위해서 특정 데이터를 저작물의 품질이나 데이터 크기의 변화없이 삽입하고, 필요시 이를 검출하는 기술이다. 워터마크가 삽입된 컨텐츠는 사람의 육안이나 청각으로 구별할 수 없어야 하고 여러 종류의 변환 또는 고의적 공격에 강인성을 가져야한다. 본 논문에서는 영상의 공간 영역과 주파수 영역에 대한 정보를 함께 갖는 웨이블릿(Wavelet) 변환영역에서 워터마킹을 수행하는 방법을 제안하였다. 제안한 방법에서는 강인성과 비가시성을 동시에 만족하기 위해 다중 임계값을 사용였다. 워터마크 삽입 위치는 상관도가 높은 부대역 계수들의 유사성을 조사하고 관련 주파수 대역에서 계수의 중요도를 검증한 뒤 워터마크를 삽입할 위치로 결정하였다. 이 때 유사성의 표현은 부대역간의 계수값 차를 이용하였고, 이 차들의 분포는 워터마크를 삽입하고 검출하는 데 사용한다. 워터마크의 검출은 부대역간의 특성을 이용함으로써 원래의 영상을 사용하지 않고 검출할 수 있다. 이러한 특성들 때문에 제안한 워터마킹 알고리즘은 JPEG 압축 공격 등을 비롯한 일반적인 영상처리에 대해 비가시성과 강인성을 동시에 만족함을 보였다.

웹접근성과 사용성을 모두 만족시키다

서영호,이경호 (사)한국인터넷전문가협회 2014 Web Korea Annual Vol.2014 No.-

시설하우스에서 저농도 돈분 액비의 연용이 토양 및 토마토와 오이의 수량에 미치는 영향

서영호,안문섭,강안석,정영상 한국토양비료학회 2011 한국토양비료학회지 Vol.44 No.5

Long-term continuous application of livestock by-products to agricultural land may adversely affect the soil characteristics and the crop yield. Five year term study from 2007 was carried out to assess the effects of repeated application of low-concentration swine slurry on soil chemical properties including phosphate and heavy metal contents and yield of tomato (Lycopersicon esculentum) and cucumber (Cucumis sativus L.) in a greenhouse. Treatments were conventional chemical fertilizers and three application rates of low-concentration swine slurry (Slurry composting and biofiltration, SCB); 50%, 100%, and 200% of recommended nitrogen fertilization. For swine slurry treatment of 50% nitrogen, deficient nitrogen was supplemented with urea fertilizer. The soil phosphorus and heavy metal contents after five year continuous application of swine slurry were not significantly higher than those of chemical fertilizer use. Repeated application of the swine slurry alone for five years resulted in relatively high soil exchangeable potassium and sodium compared with chemical fertilizer treatment. Contents of heavy metals in leaves of tomato and cucumber did not show significant difference among treatments. Yields of the crops for the swine slurry were not significantly different from that of chemical fertilizer. The results imply that continuous application of the swine slurry may not influence levels of soil phosphate and trace elements in greenhouse soils but could accumulate potassium and sodium in the soil.

Differential diagnostic factors of type 1 and type 2 myocardial infarction in patients with elevated cardiac troponin levels

서영호,백진휘,신승열,김아진,강수 대한응급의학회 2020 Clinical and Experimental Emergency Medicine Vol.7 No.3

Objective Emergency physicians experience difficulty in determining the disposition of patients with elevated troponin I levels using emergency room tests. In this study, we aimed to investigate factors that could discriminate between the occurrence of type 1 myocardial infarction (T1MI) and type 2 myocardial infarction (T2MI) in patients with elevated troponin I levels. Methods Patients admitted to the emergency department between January 1, 2017 and June 30, 2017 with elevated troponin I levels who underwent subsequent cardiac biomarker testing were included. Samples for baseline blood tests, such as cardiac biomarker levels, were collected within approximately 10 minutes of admission. Electrocardiogram, transthoracic echocardiography, and percutaneous coronary intervention results were retrospectively examined via patient report and chart reviews. Results During the study period, 169 of 234 (72%) patients were diagnosed with T2MI and 65 (28%) were diagnosed with T1MI. Among various factors, typical chest pain (odds ratio [OR], 4.40; 95% confidence interval [CI], 1.46 to 13.24; P=0.008), high troponin I levels (OR, 1.50; 95% CI, 1.19 to 1.90; P<0.001), high cholesterol (OR, 1.01; 95% CI, 1.00 to 1.02; P=0.008), and low D-dimer levels (OR, 0.87; 95% CI, 0.77 to 0.98; P=0.027) were significantly associated with T1MI incidence. Conclusion Our findings in this study indicate that typical chest pain, high levels of troponin I and cholesterol, and low levels of D-dimer were associated with the diagnosis of T1MI. Further studies are suggested to determine the cut-off values for accurate diagnosis of T1MI in the ED.

프레넬릿 기반의 디지털 홀로그램 부호화를 위한 쿼드트리 부대역 양자화기 설계

서영호,김문석,김동욱,Seo, Young-Ho,Kim, Moon Seok,Kim, Dong-Wook 한국정보통신학회 2015 한국정보통신학회논문지 Vol.19 No.5

In this paper, we propose a new subband quantizer which is a type of quad-tree for applying to digital hologram compression based on Fresenelet transform. After executing Fresnelet transform to the captured digital holgoram, we analyze effect of the designed quantizer for the reconstructed objects from analyzing average energy of each coefficient and visual importance in all subbands. We analyze distribution of coefficient and set dynamic range for each subband, and then design subband quantizer. For enhancing effectiveness of the designed quantize, we adopt a method using the coefficients which are located out of dynamic range, which are named by exception indices. From this, we can obtain more effective quantizer which has higher performance in a range of σ′ = 5.0. 본 논문에서는 프레넬릿 변환을 이용하여 디지털 홀로그램을 압축할 경우에 사용될 수 있는 쿼드트리 형태의 부대역 양자화기를 제안한다. 획득된 디지털 홀로그램에 대해서 프레넬릿 변환을 수행한 후에 각 부대역별로 화소당 평균 에너지와 부대역의 시각적인 중요도를 분석하여 부대역이 복원 영상에 비치는 영상을 분석하였다. 각 부대역별로 계수들의 분포를 분석하여 다이나믹 영역을 정하고, 부대역 양자화기를 설계하였다. 설계한 양자화기의 효율을 높이기 위해서 다이나믹 영역 외의 영역에 존재하는 계수를 활용하는 방법을 적용하였고, 이를 예외 계수라 하였다. 그 결과 σ′ = 5.0인 범위에서 높은 성능을 가질 수 있는 양자화기를 설계하였다.

워크플로우 관리시스템의 객체지향적 설계 및 구현

서영호,김영호,강석호 대한산업공학회 1998 대한산업공학회 추계학술대회논문집 Vol.1998 No.10