• Journal of the Korean Society for Precision Engineering
• /
• v.12 no.6
• /
• pp.80-86
• /
• 1995

A method of eliminating the branch problem in driving crank center point plane for 3 position synthesis of 4 bar mechanism is introduced. By studying various transformation characteristics from the circle point plane into the center poi t plane, the curves in the center point plane transformed from the filemon line in circle point plane are analytically obtained, which will seperate the whole center point plane into many sub-areas for the selec- tion of the center point of the driving crank. And a simple method to identify which of the sub-areas will cause the branch problem is also presented. The method will allow the selection of the center point of driving crank without the branch problem.

• Smart Structures and Systems
• /
• v.20 no.5
• /
• pp.563-572
• /
• 2017

The safety of structures is closely associated with the structural out-of-plane behavior. In particular, long and slender beam structures have been increasingly used in the design and construction. Therefore, an evaluation of the lateral and torsional behavior of a structure is important for the safety of the structure during construction as well as under service conditions. The current contact measurement method using displacement meters cannot measure independent movements directly and also requires caution when installing the displacement meters. Therefore, in this study, a vision-based system was used to measure the in-plane and out-of-plane displacements of a structure. The image processing algorithm was based on reference objects, including multiple targets in Lab color space. The captured targets were synchronized using a load indicator connected wirelessly to a data logger system in the server. A laboratory beam test was carried out to compare the displacements and rotation obtained from the proposed vision-based measurement system with those from the current measurement method using string potentiometers. The test results showed that the proposed vision-based measurement system could be applied successfully and easily to evaluating both the in-plane and out-of-plane movements of a beam including twisting rotation.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1998.10a
• /
• pp.513-518
• /
• 1998

In Half Precast Concrete Method, such as composite slab and composite wall, Interface between half PC plate and cast-in-place concrete is occurred. And this interface endure lastly in-plane shear which is occurred by external force. Therefore, test was executed to study in-plane shear strength of interface between half PC plate and cast-in-place concrete. In this test, Experimental parameters are finishing condition of the interface, cohesion of concrete, existence and nonexistence of re-bar truss, and angle and direction of lattice of re-bar truss. Comparing and analyzing experimental results, conclusions are obtained as follows. (1) In-plane shear strength of wide interface in composite plate is more affected by the roughness of interface than re-bar truss. And cohesion of concrete contribute to increasing in-plane shear strength. Therefore it seems that the interface should be roughen and kept clean to improve in-plane shear strength. (2) It seems that shear friction equation in ACI code can be sagely available for design of in-plane shear of composite plate.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.26 no.3
• /
• pp.229-237
• /
• 2000

According to the functional matrix theory, Delaire proposes that individual occlusal plane was determined by variable effects of teeth, maxilla, mandible, cranium, cranial base and soft tissue matrix including the orofacial musculature. and that there is the ideal occlusal plane determined by the most proper spatial position of maxilla and mandible, functionally and esthetically. This study was designed to find out the relation between Delaire's ideal occlusal plane and muscle activity of masticatory muscles in individuals who have normal maxillo-mandibular relationships. Lateral cephalometric radiographs were taken and his/her individual occlusal plane and ideal occlusal plane were analyzed with Delaire's architectural and structural craniofacial analytic method. For evaluation of muscle activities of masticatory muscles, electromyography of anterior temporal muscle, superficial masseter muscle, and anterior belly of digastric muscle was recorded in fifty Korean normal Angle class I occlusion individuals. According to the average value of ideal occlusal plane, fifty normal Angle class I occlusion individuals were classified into three groups: Ideal occlusal plane group(I group), hyperrotation group(I+ group) and hyporotation group(I- group). The result of this study was as follows: 1. The results of Delaire's architectural and structural craniofacial analysis of lateral cephalography of the fifty Korean normal Angle class I occlusion individuals are that twelve persons(24%) have consistent or parallel with ideal occlusal plane and the average of angular difference was $1.22^{\circ}{\pm}3.69^{\circ}$. 2. There is no significant difference in muscle activities of masticatory muscles during resting(p<0.05), but significant increases of muscle activity of ipsilateral anterior temporal and masseter muscle, contralateral anterior belly of digastric muscle during unilateral chewing and of anterior temporal and masseter muscle during bilateral clenching(p<0.05). 3. To find out the effect of the angular difference between Delaire's ideal occlusal plane and real occlusal plane to muscle activity, muscle activities of masticatory muscles were compared with three groups in each other; I group, I+ group and I- group. The results were no significant differences during resting, unilateral chewing and bilateral clenching.(p>0.05) 4. Although there is no significant differences of masticatory muscle activities among the three groups, the fact that increasing tendency of masseter muscle activity of ideal occlusal plane group(I+) than those of any other groups(I+ and I-) during bilateral clenching was noted. There is only the implication that occlusal plane makes some effects on masticatory muscle activities, espacially that of masseter muscle during bilateral clenching. In conclusion, the hypothesis that occlusal plane is one of the factors which affect the muscle activities of masticatory muscles and that anyone whose occlusal plane consistent with Delaire's ideal occlusal plane has an extraordinary functional advantage in masticatory muscle function cannot be proven with electromyography methods.

• Korean Journal of Computational Design and Engineering
• /
• v.6 no.1
• /
• pp.31-39
• /
• 2001

Presented in this paper are algorithms to compute the positions of vertices and equations of edges of the Voronoi diagram of a circle set. The circles are located in a Euclidean plane, the radii of the circles are not necessarily equal and the circles are not necessarily disjoint. The algorithms correctly and efficiently work when the correct topology of the Voronoi diagram was given. Given three circle generators, the position of the Voronoi vertex is computed by treating the plane as a complex plane, the Z-plane, and transforming it into another complex plane, the W-plane, via the Mobius transformation. Then, the problem is formulated as a simple point location problem in regions defined by two lines and two circles in the W-plane. And the center of the inverse-transformed circle in Z-plane from the line in the W-plane becomes the position of the Voronoi vertex. After the correct topology is constructed with the geometry of the vertices, the equations of edge are computed in a rational quadratic Bezier curve farm.

• Journal of the Society of Naval Architects of Korea
• /
• v.40 no.1
• /
• pp.28-35
• /
• 2003

Fatigue tests of transverse fillet weldment were performed under out-of-plane bending loads. Significant increase of the fatigue strength was observed under out-of-plane bending loads, compared to the one under in-plane loads (axial loads). Applicability of the crack propagation analysis using LEFM for the surface crack of fillet weldment were investigated as well, in parallel with the fatigue tests. For the rational assessment of the fatigue strength of welded ship structures where combined stresses of the in-plane axial stress and the out-of-plane bending stress are induced simultaneously due to complexity of applied load and structural geometry, further investigation is recommended for the effect of the out-of-plane bending stress on the fatigue strength of weldment.

• Clinics in Shoulder and Elbow
• /
• v.21 no.3
• /
• pp.113-119
• /
• 2018

Background: This study was undertaken to evaluate the positional relationship between planes of the glenoid component (the scapular plane and the perpendicular plane to the glenoid) and its surrounding structures. Methods: Computed tomography (CT) images of both shoulders of 100 patients were evaluated using the 3-dimensional CT reconstruction program ($Aquarius^{(R)}$; TeraRecon). We determined the most lateral scapular bony structure of the scapular plane and measured the shortest distance between the anterolateral corner of the acromion and the scapular plane. The distance between the scapular plane and the midpoint of the line connecting the posterolateral corner of acromion and the anterior tip of the coracoid process (fulcrum axis) was also evaluated. The perpendicular plane was then adjusted to the glenoid and the same values were re-assessed. Results: The acromion was the most lateral scapular structure of scapular plane and perpendicular plane to the glenoid. The average distance from the anterolateral corner of the acromion to the scapular plane was $10.44{\pm}5.11mm$, and to the plane perpendicular to the glenoid was $9.55{\pm}5.13mm$. The midpoint of fulcrum axis was positioned towards the acromion and was measured at $3.90{\pm}3.21mm$ from the scapular plane and at $3.84{\pm}3.17mm$ from the perpendicular plane to the glenoid. Conclusions: Our data indicates that the relationship between the perpendicular plane to the glenoid plane and its surrounding structures is reliable and can be used as guidelines during glenoid component insertion (level of evidence: Level IV, case series, treatment study).

• Journal of the Korean Society for Precision Engineering
• /
• v.15 no.11
• /
• pp.121-129
• /
• 1998

In-plane ESPI(Electronic Speckle Pattern Interferometry) was devised to measure in-plane deformations and rotation of a specimen with laser in this study. ESPI is a optical measuring method to be able to measure the deformations of engineering components and materials in industrial fields. The conventional measuring methods of surface deformations such as the strain gauge have many demerits because they are contact and point-to-point measuring ones. But that ESPI is noncontact, nondestructive and whole field measuring method can overcome previous disadvantages. We used ESPI which is sensitive to in-plane displacement for measuring in-plane deformations of a disk. And the 4-frame phase shifting method was used for the quantitative analysis. First of all, the system calibration was done due to an in-plane rotation before getting deformations of a disk. Finally we showed good agreement between the experiment results and those of the FEA(Finite Element Analysis).

• The Mathematical Education
• /
• v.46 no.4
• /
• pp.493-502
• /
• 2007

What is a foundational element of plane geometry? Isn't it possible to constitute the contents of plane geometry from that element? In this paper, we suggest a view point that triangle is a foundational element of plane geometry. And take some examples of reconstruction of usually given contents and mathematical activity centered on the triangle in plane geometry.

• Journal of Digital Convergence
• /
• v.12 no.12
• /
• pp.441-447
• /
• 2014

The purpose of this study was to explore differences of spinal stabilization muscle strength between groups classified by BMI for industrial workers. Fifty subjects participated in this study were divided to obesity group(BMI over $25kg/m^2$) and non obesity group(BMI under $25kg/m^2$). Independent t-test was applied for analysis. The results showed the following. There were significant differences in $0^{\circ}$ Forward on sagittal plane, in both $90^{\circ}$ Left, $90^{\circ}$ Right on coronal plane, in $45^{\circ}$ Left Tilt, $45^{\circ}$ Right Tilt on diagonal plane between groups. Last, There were significant differences in an amount of soft lean muscle and an amount of skeletal muscle between groups. These results shows that spinal stabilization muscle strength program for the obese should be considered in sagittal plane, coronal plane, and diagonal plane.