• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 2006년도 정기 학술대회 논문집
• /
• pp.963-968
• /
• 2006

The main purpose of this paper is to investigate the stability of water tower with a relatively small footing. The water tower is modeled that the column carrying a container is supported by a rotational spring at the base and is of constant cross-section, with a weight per unit length of column axis. The column model is based on the Bernoulli-Euler beam theory. The Runge-Kutta method and Determinant Search method are used to perform the integration of the governing differential equation and to determine the critical values(critical own weight. and critical buckling load), respectively. The critical buckling loads are calculated over a range of system parameters: the rotational stiffness parameter, the dimensionless radius of container and the own weight parameter of the column. The relation between the rotational stiffness parameter and the critical own weight parameter of the column is analyzed.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 2003년도 가을 학술발표회 논문집
• /
• pp.277-284
• /
• 2003

One of important problem, in large space structure, is to overcome the self-weight of roof structure. This problem can be solved with using tension members effectively. Thus the rapid progress of hybrid structure, that makes effective use of the means of settling, has a good effect on realizing the large space. These systems of hybrid structure have the advantages of light weight and its own internal redundancy, but are occurred unstable phenomenon such as bifurcation or snap-through buckling, when the load level is come to the critical point. Among the hybrid structure, cable dome is shown the strong nonlinearity of unstable phenomenon in accordance with the external force. Therefore, the purpose of this study is to analyze and verify comparatively the unstable phenomenon of the Geiger and Flower type cable dome structures under axismmetric load.

• 대한가정학회지
• /
• 제45권4호
• /
• pp.113-122
• /
• 2007

The purpose of this study was to investigate weight control and the relative influence of individual variables affecting children's attempts to control weight. The study subjects were 319 elementary school children. First, the average body height and weight of the children who participated in this study was somewhat larger in boys and similar in girls, as compared with the normal body shape of Korean children. More boys were classified as overweight than girls, based on BMI. Both boys and girls were dissatisfied with their body shape, and especially the girls showed higher dissatisfaction rate than the boys did. Almost half of the children were concerned about weight control and girls had higher concern than boys. Of the children, 38.8% had controlled their weight; however there was no difference between their sexes. There were significant differences between children who had and had not experienced weight control in the following variables: stress caused by obesity, body satisfaction, BMI, subjective body shape perception and concern about weight control. Therefore, discriminant function analysis was performed to determine the discrimination of these variables between the two groups. From the analysis results, the most critical factor was BMI in the boys and concern about weight control in the girls. This finding should be reflected in the design of weight control programs for children i.e., boys should be encouraged to perceive correctly their own body shape and to control weight by maintaining a well-balanced diet and moderate exercise over a long period of time, rather than by skipping meals, while girls should be inspired with sound values and attitudes regarding their body shape, rather than provided with the concrete information on how to control weight.

• 대한토목학회논문집
• /
• 제4권1호
• /
• pp.93-101
• /
• 1984

본(本) 논문(論文)에서는 일정변단면장주(一定變斷面長柱)의 탄성임좌굴하중(彈性臨挫屈荷重)을 구하는 각산식(咯算式)을 제시(提示)하였다. 특히, 고가도로설계시(高架道路設計時) 자주 나타나는 일단고정(一端固定) 타단자유(他端自由)인 중실원형(中實圓形) 및 구형단면(矩形斷面)에 한(限)하였다. 처짐곡선 미분방정식(微分方程式)의 정밀해(精密解)는 Bessel 함수(凾數)로 나타나는데, Bisection method를 이용하여 Computer로 수치해석(數値解析)하였다. 또 자중(自重)고려시 F.E.M에 의한 해석(解析)은 고유치(固有値) 문제(問題)가 되므로 Jacobi method를 이용하여 수치해석(數値解析)하였고, 균일단면장주(均一斷面長柱)의 정밀해(精密解)와 비교(比較)하여 F.E.M에 의한 근사해(近似解)의 신뢰도(信賴度)를 높였다. 그 결과(結果) 일정변단면장주(一定變斷面長柱)의 임계좌굴하중(臨界挫屈荷重)은 형상계수(形狀係數)와 단면변화율(斷面變化率)에 대해 균일단면장주(均一斷面長柱)의 비례식(比例式)으로 나타낼 수 있었다.

• Smart Structures and Systems
• /
• 제6권7호
• /
• pp.867-887
• /
• 2010

An energy-based variational approach is used for structural dynamic modeling of the IPMC (Ionic Polymer Metal Composites) flapping wing. Dynamic characteristics of the wing are analyzed using numerical simulations. Starting with the initial design, critical parameters which have influence on the performance of the wing are identified through parametric studies. An optimization study is performed to obtain improved flapping actuation of the IPMC wing. It is shown that the optimization algorithm leads to a flapping wing with dimensions similar to the dragonfly Aeshna Multicolor wing. An unsteady aerodynamic model based on modified strip theory is used to obtain the aerodynamic forces. It is found that the IPMC wing generates sufficient lift to support its own weight and carry a small payload. It is therefore a potential candidate for flapping wing of micro air vehicles.

• 대한임베디드공학회논문지
• /
• 제10권5호
• /
• pp.273-279
• /
• 2015

The vehicle has lots of embedded systems. Each of systems has its own role. In case of the vehicle, simple failure of system can be critical to driver. Therefore all of embedded system should be managed based on importance factors to be effective. In this paper, we consider the resilience as the importance factor for the driving system with ACC(Adaptive Cruise Control). We propose metrics to calculate the resilience of the embedded system. To get the resilience of system, we calculate the reliability and the resilience of nodes in the system using its failure rate. The resilience of whole system can be presented by the resilience of nodes and its weight. We calculate the resilience and compare the centralized structure and the distributed structure.

• 대한영양사협회학술지
• /
• 제2권1호
• /
• pp.20-28
• /
• 1996

In Korea, nutritional services have not been included in the periodic medical examinations for employees. Naturally, the practice of individual dietary treatment, or nutrition education, has not yet been implemented, specifically for employees who are expected to encounter health problems. This study was designed to evaluate the necessity and development of nutritional consultations during medical examinations of employees and of worksite nutrition programs. One hundred and five employees from three companies were chosen as subjects for this study. As a result, the average intake of nutrients were found to be sufficient for male employees but female employees were found to be deficient in their intake of total calories, calcium, iron, vitamins A and $B_2$. Also, most of employees did not recognize their own blood cholesterol levels, blood pressure, or blood sugar level. Many employees thought that they needed nutritional consultation during periodic medical examinations and during worksite nutrition programs that also include programs for the whole family. According to the results, clinics for weight control were urgently demanded among several nutrition programs. It should be noted that weight problems, high blood cholesterol levels, diabetes, and other health problems were frequently found in companies whose employees had relatively minimal knowledge about nutrition information. In an effort to prevent disease, the worksite nutrition programs and other nutritional services for employees are critical. This study, therefore, suggests to include nutritional services in medical examinations and to develop efficient worksite nutrition programs.

• 미술이론과 현장
• /
• 제13호
• /
• pp.133-156
• /
• 2012

This paper briefly charts the history of excrement as part of the late 20th-century art and explores ways in which excrement functions in the realms of 'High' art. From Piero Manzoni's to David Hammons' performance , excrement has taken a small yet distinctively important part in the development of contemporary art. In an attempt to challenge the hegemony of 'high' art, on the one hand, and resist the commercialization and fetishization of art, on the other, Manzoni allegedly offered his own "shit" preserved in a tin can and sold it at the price of gold of the same weight. Andy Warhol took the legendary Abstract-Expressionist painter Jackson Pollock as the object of parody, simulating Pollock's dripping action by pissing onto the canvas that had been primed with copper-based paint. Warhol's urination produced splashes and stains of iridescent colors just as the patterns on ordinary abstract paintings. In contrast to Pollock's masculine action, Warhol's pissing alludes to the artist's homosexuality. Excrements in art also provoked controversies, debates, and even acts of vandalism against the artworks. The works of Andres Serrano and Chris Ofili infuriated many Christians for the blasphemous use of excrement with religious icons. Politicians engaged in the heated debates on the use of public and national funds in support of some of the 'politically incorrect' contemporary art. In the midst of media sensation and criticisms, these works challenged the conventional understanding of artistic beauty. The preexisting artworks were also targeted. African-american artist Hammons assumed the role of spectator in by urinating on Richard Serra's sculpture in the street of New York City. It was an act condemnation levelled at the racist pattern of the way in which large portions of funds and commisions of "public" art tended to promote established 'white' artists, whose work or creative process often failed to reflect the actual public. The use of excrement in art is not unusual in contemporary art practices. With its subversive power, excrement plays an important critical roles in the shaping of contemporary art.

• Structural Engineering and Mechanics
• /
• 제39권2호
• /
• pp.241-266
• /
• 2011

The Self Compacting Concrete, SCC is the new generation type of concrete which is not needed to be compacted by vibrator and it will be compacted by its own weight. Since SCC is a new innovation and also the high strength self compacting concrete, HSSCC behavior is like a brittle material, therefore, understanding the strength effect on the serviceability performance of reinforced self compacting concretes is critical. For this aim, first the normal and high strength self compacting concrete, NSSCC and HSSCC was designed. Then, the serviceability performance of reinforced connections consisting of NSSCC and HSSCC were investigated. Twelve reinforced concrete connections (L = 3 m, b = 0.15 m, h = 0.3 m) were simulated, by this concretes, the maximum and minimum reinforcement ratios ${\rho}$ and ${\rho}^{\prime}$ (percentage of tensile and compressive steel reinforcement) are in accordance with the provision of the ACI-05 for conventional RC structures. This study was limited to the case of bending without axial load, utilizing simple connections loaded at mid span through a stub (b = 0.15 m, h = 0.3 m, L = 0.3 m) to simulate a beam-column connection. During the test, concrete and steel strains, deflections and crack widths were measured at different locations along each member. Based on the experimental readings and observations, the cracked moment of inertia ($I_{cr}$) of members was determined and the results were compared with some selective theoretical methods. Also, the flexural crack widths of the members were measured and the applicability for conventional vibrated concrete, as for ACI, BS and CSA code, was verified for SCCs members tested. A comparison between two Codes (ACI and CSA) for the theoretical values cracking moment is indicate that, irrespective of the concrete strength, for the specimens reported, the prediction values of two codes are almost equale. The experimental cracked moment of inertia $(I_{cr})_{\exp}$ is lower than its theoretical $(I_{cr})_{th}$ values, and therefore theoretically it is overestimated. Also, a general conclusion is that, by increasing the percentage of ${\rho}$, the value of $I_{cr}$ is increased.

• 폴리머
• /
• 제31권2호
• /
• pp.98-104
• /
• 2007

다양한 분자량의 폴리스티렌을 벤젠/n-헵탄, 1,4-다이옥산/이소프로판올, 1,4-다이옥산/n-헵탄과 같은 3종류의 혼합용매 계에 녹인 뒤 온도 상승에 따른 사슬의 팽창거동을 Flory $\Theta$온도 이상에서 점성도법으로 측정하였다. 온도 상승에 따라 두 종류의 영역, 즉 고분자 사슬이 팽창하는 영역과 수축하는 영역으로 구별되며, 분자량이 클수록 최대팽창온도가 높게 나타났다. 하나의 혼합용매 계 내에서는 $\tau/\tau_c$ 파라미터로 서로 다른 분자량의 사슬 팽창에 대하여 만능성이 나타나지만 서로 다른 혼합용매 계 사이에서는 각각의 기울기를 보임으로써 만능성이 관찰되지 않았다. 그러나 새로운 실험적 $b^{2/3}\tau/\tau_c$ 파라미터를 도입할 경우 모든 혼합용매 계의 사슬 팽창의 데이터들은 하나의 직선 위에 놓임으로써 만능성은 다시 회복되었다. 여기서 $\tau$는 $(T-\Theta)/\Theta$로 $\tau_c$는 $(\Theta-T_c)/T_c$로 각각 정의되며, $T_c$는 임계용액온도를 의미하며, b는 Schultz-Flory 식에서 $1/T_c$의 $1/M_w^{1/2}$에 대한 유효 기울기이다.