• Journal of the Chungcheong Mathematical Society
• /
• v.24 no.2
• /
• pp.313-317
• /
• 2011

In this article, we consider an unbounded minimal graph $M{\subset}R^3$ which is contained in a slab. Assume that ${\partial}M$ consists of two Jordan curves lying in parallel planes, which is symmetric with the reflection under a plane. If the asymptotic behavior of M is also symmetric in some sense, then we prove that the minimal graph is itself symmetric along the same plane.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.20 no.3
• /
• pp.549-557
• /
• 2016

It is important for effective visualization to summarize not only a large amount of debugging information but also the mental models of abstract ideas. This paper presents an abstract visualization tool which provides effective visualization of thread structure and race information for OpenMP programs with critical sections and nested parallelism, using a partial order execution graph which captures logical concurrency among threads. This tool is supported by an on-the-fly trace-filtering technique to reduce space complexity of visualization information, and a graph abstraction technique to reduce visual complexity of nested parallelism and critical sections in the filtered trace. The graph abstraction of partial-order relation and race information is effective for understanding program execution and detecting to eliminate races, because the user can examine control flow of program and locations of races in a structural fashion.

• Economic and Environmental Geology
• /
• v.33 no.4
• /
• pp.249-260
• /
• 2000

The development of dual volcanic chains, parallel to the trend of the subduction trench, is observed in the southern part of Korea. Elsewhere on the Earth volcanic arcs dominantly consist of two such chains. In the southern part of Korea, two volcanic chains within a single volcanic arc was developed. Kyongsang basin, where the first volcanic chain located, and Youngdong-Kwangju depression zone where the second volcanic zone located, showed sub-parallel volcanic rock distributed areas. Concentrations of incompatible elements in the southern part of Korea samples show clear across-arc variations, with lavas from the first volcanic chain being most depleted in these elements, all incompatible element concentrations increase towards the second volcanic chain. The above across-arc variation may be caused by the difference in solid phases coexisting with the fluid phases during the dehydration processes. The concentrations of incompatible elements, Zr/Y ratios, and Rb/K ratios indicate that the second volcanic chain (Youngdong-Kwangiu depression zone) was generated by low degrees of partial melting at the deeper depth compared to the conditions of the first volcanic chain (Kyongsang basin) and residual garnet probably attributed to the their partial melting.

• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.2737-2742
• /
• 2003

Kinematic calibration enhances absolute accuracy by compensating for the fabrication tolerances and installation errors. Effectiveness of calibration procedures depends greatly on the measurements performed. While the Cartesian postures are measured completely, all of the geometric parameters can be identified to their true values. With partial pose measurements, however, few geometric parameters may not be identifiable and effectiveness of the calibration results may vary significantly within the workspace. QR decomposition of the identification Jacobian matrix can reveal the non-identifiable parameters. Selecting postures for measurement is also an important issue for efficient calibration procedure. Typically, the condition number of the identification Jacobian is minimized to find optimum postures. This paper investigates identifiable parameters and optimum postures for four different calibration procedures - measuring postures completely with inverse kinematic residuals, measuring postures completely with forward kinematics residuals, measuring only the three position components, and restraining the mobility of the end-effector using a constraint link. The study is performed for a six degree-of-freedom fully parallel HexaSlide type paralle manipulator, HSM. Results verify that all parameters are identifiable with complete posture measurements. For the case of position measurements, one and for the case of constraint link, three parameters were found non-identifiable. Optimal postures showed the same trend of orienting themselves on the boundaries of the search space.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2011.11a
• /
• pp.830-834
• /
• 2011

In this study, we performed three-dimensional CFD analysis to investigate the effect of the rotor blade sweep of a partial admission supersonic turbine on the stage performance and the flow field. The computations are conducted for three different sweep cases, No sweep(NSW), Backward sweep(BSW), and Forward sweep(FSW), using flow analysis program, $FLUENT^{TM}$ 6.3 Parallel. The results show that BSW model give the effect on the reducing of mass flow rates of tip leakage and the increasing of t-to-s efficiency.

• Korean Journal of Mathematics
• /
• v.16 no.2
• /
• pp.215-231
• /
• 2008

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.

• Journal of the Korean Ceramic Society
• /
• v.30 no.9
• /
• pp.717-722
• /
• 1993

Effects of microstructures on the electrical properties of ZrO2 based ceramics were analyzed by modeling layer arrangements and mixed phase structures. Single layers and alternating multilayers were made from 3mol% and 8mol% Y2O3 doped ZrO2 powders, while mixed specimen was made by blending and compacting these raw powders. After sintering at 150$0^{\circ}C$ for 2hr in air, AC impedance characteristics were measured. Contributiion of bulk comonent to total resistivity and its temperature-dependence were larger in 8Y-ZrO2 single layer than in 3Y-ZrO2 single layer. The multilayered specimen connected in serial to electrodes showed partial characteristics of both 3Y-ZrO2 and 8Y-ZrO2 single layers. The multilayered specimen connected in parallel to electrodes and the mixed specimen exhibited characteristics mainly of 8Y-ZrO2 single layer. The multilayered specimen connected in parallel to electrodes revealed the highest electrical conductivity near the operating temperature of solid oxide fuel cell. However, it is expected that the mixed specimen is appropriate for the applications because of its relatively high electrical conductivity with high strength expected.

• The KIPS Transactions:PartA
• /
• v.8A no.2
• /
• pp.117-124
• /
• 2001

At NOW (Networks Of Workstations), the load sharing is very important role for improving the performance. The known load sharing strategy is fixed-granularity, variable-granularity and adaptive-granularity. The variable-granularity algorithm is sensitive to the various parameters. But Send algorithm, which implements the fixed-granularity strategy, is robust to task granularity. And the performance difference between Send and variable-granularity algorithm is not substantial. But, in Send algorithm, the computing time and the communication time are not overlapped. Therefore, long latency time at the network has influence on the execution time of the parallel program. In this paper, we propose the preSend algorithm. In the preSend algorithm, the master node can send the data to the slave nodes in advance without the waiting for partial results from the slaves. As the master node sent the next data to the slaves in advance, the slave nodes can process the data without the idle time. As stated above, the preSend algorithm can overlap the computing time and the communication time. Therefore we reduce the influence of the long latency time at the network and the execution time of the parallel program on the NOW. To compare the execution time of two algorithms, we use the $320{\times}320$ matrix multiplication. The comparison results of execution times show that the preSend algorithm has the shorter execution time than the Send algorithm.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.32 no.1
• /
• pp.77-91
• /
• 2007

In this paper, we present a symbiotic evolutionary algorithm for multi-objective optimization. The goal in multi-objective evolutionary algorithms (MOEAs) is to find a set of well-distributed solutions close to the true Pareto optimal solutions. Most of the existing MOEAs operate one population that consists of individuals representing the entire solution to the problem. The proposed algorithm has a two-leveled structure. The structure is intended to improve the capability of searching diverse and food solutions. At the lower level there exist several populations, each of which represents a partial solution to the entire problem, and at the upper level there is one population whose individuals represent the entire solutions to the problem. The parallel search with partial solutions at the lower level and the Integrated search with entire solutions at the upper level are carried out simultaneously. The performance of the proposed algorithm is compared with those of the existing algorithms in terms of convergence and diversity. The optimization problems with continuous variables and discrete variables are used as test-bed problems. The experimental results confirm the effectiveness of the proposed algorithm.

• Journal of the Korean Institute of Telematics and Electronics C
• /
• v.36C no.3
• /
• pp.17-25
• /
• 1999

This paper proposes a new bit-serial multiplier/divider architecture to reduce the hardware complexity significantly and to maintain the same number of cycles compared with existing architectures. Since the proposed bit-serial multiplier/divider architecture does not extend the number of bits in registers and an adde $r_tractor to calculate a partial product or a partial remainder, the hardware overhead can be greatly reduced. In addition, the proposed architecture can perform an additio $n_traction and a shift operation in parallel and the number of cycles for $\textit{N}$-bit multiplication and division for the proposed circuits is $\textit{N}$ and $\textit{N}$ + 2, repectively. Thus, the number of cycles for multiplication and division is the same compared with existing architectures. The SliM Image Processor employs the proposed multiplier/divider architecture and proves the performance of the proposed architecture.cture.