• Journal of Korea Spatial Information System Society
• /
• v.9 no.3
• /
• pp.67-80
• /
• 2007

Recently, many studies on query processing algorithms has been done for spatial networks, such as roads and railways, instead of Euclidean spaces, in order to efficiently support LBS(location-based service) and Telematics applications. However, both a closest pairs query and an e-distance join query require a very high cost in query processing because they can be answered by processing a set of POIs, instead of a single POI. Nevertheless, the query processing cost for closest pairs and e-distance join queries is rapidly increased as the number of k (or the length of radius) is increased. Therefore, we propose both a closest pairs query processing algorithm and an e-distance join query processing algorithm using a POI-based materialization technique so that we can process closest pairs and e-distance join queries in an efficient way. In addition, we show the retrieval efficiency of the proposed algorithms by making a performance comparison of the conventional algorithms.

• Journal of Korea Game Society
• /
• v.19 no.1
• /
• pp.5-14
• /
• 2019

This paper presents a practical method to compute the closest approach distance of two ellipsoids in their inter-center direction. This is the key technique for collision handling in the dynamic simulation of rigid and deformable bodies approximated with ellipsoids. We formulate a set of equations with the inter-center distance and the contact point and normal for the two ellipsoids contacting each other externally. The equations are solved using fixed-point iteration and Aitken's delta-squared process. In addition, we introduce a novel stopping criterion expressed in terms of the error in distance. We demonstrate the efficiency and practicality of our method in various experiments.

• Journal of Korea Game Society
• /
• v.19 no.6
• /
• pp.99-106
• /
• 2019

This paper addresses a method to compute the closest approach distance between two ellipsoids in their inter-center direction. This is the key technique for collision detection and response between ellipsoids. We formulate a set of conditions with the inter-center distance, the contact point and the contact normal vector of the two externally-contacting ellipsoids. The equations are solved robustly and efficiently using a hybrid of Newton's method and the bisection method with root bracketing. We demonstrate the robustness and efficiency of the proposed method in various experiments.

• Journal of Family Relations
• /
• v.23 no.2
• /
• pp.111-131
• /
• 2018

Objectives: This study examined the effects of residential proximity to adult children on the mental and physical health of middle-aged and older parents. The study also evaluated whether the parental age and gender of the adult child in closest proximity to the parent might moderate the association. Method: Data were drawn from five waves of the Korean Longitudinal Study of Aging(2006-2014). The analytic sample consisted of 7,359 parents aged 45 or older who had at least one non-coresidential adult child aged 19 or older. The analyses were conducted by estimating a series of fixed effects models while adjusting for the nested structure of the data. Results: The results showed that first, a closer distance between an adult child and the parent was generally associated with the parent experiencing a decrease in depressive symptoms. Yet, the mental health benefit was smaller for parents aged 65 years or older whose closest living adult child was a son. Second, a closer distance was observed to affect chronic illness only among middle-aged parents (aged 45 to 64). When the closest living adult child was a daughter, the middle-aged parent experienced deterioration in their chronic illness. On the other hand, the opposite pattern was observed when the closest living adult child was a son. Conclusions: The parental age and gender of the adult child in closest proximity to the parent might have varying effects on parents' health. A closer distance between an adult child and their parent has a positive impact on the mental health of the parent as a whole, whereas the effect of living closer was mixed in relation to the parental physical health.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.19 no.5
• /
• pp.1259-1268
• /
• 1995

The stress distribution around micro holes and the behavior of stress interaction between micro holes are considerd in the study. Several conclusions are extracted as follows : (1) The stress interaction varies with the distance e between micro holes. When the two micro holes are spaced in such a manner that theri two closest points are separated by a distance of micro hole radius (e=1), stress distribution is affected by a opposite micro hole in all the closest region. In addition, if two closest points are seperated by twice the distance of a micro hole radius (e=2), stress distribution is affected by a opposite micro hole in the region of -0.8.leq.x/r.leq.0.8 and the interaction effect can be neglected for e=4. (2)If the depth becomes larger than the radius, or the radius varies, the shape and magnitude of stress distribution around micro holes varies. (3) Hoop stress around a micro hole for the two dimensional configuration is larger than that of the three dimensional micro hole located on the surface of material for .theta. < 60.deg., but it is reversed for .theta > 60.deg.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• v.1
• /
• pp.31-36
• /
• 2006

The evaluation of safety of simulated maneuvers is frequently analysed by so called goal line or point of interest. This paper is to suggest that regarding the results of simulation the goal analysis and in length analysis are investigated respectively and the availability of which is effective and is also to suggest closest distance to channel boundary at each ship's position, not centerline, as one of proximity measures.

• KIPS Transactions on Software and Data Engineering
• /
• v.5 no.9
• /
• pp.401-410
• /
• 2016

3D registration is a computer vision technique of aligning multi-view range images with respect to a reference coordinate system. Various 3D registration algorithms have been introduced in the past few decades. Iterative Closest Point (ICP) is one of the widely used 3D registration algorithms, where various modifications are available nowadays. In the ICP-based algorithms, the closest points are considered as the corresponding points. However, this assumption fails to find matching points accurately when the initial pose between point clouds is not sufficiently close. In this paper, we propose a new method to solve this problem using the 6D distance (3D color space and 3D Euclidean distances). Moreover, a color segmentation-based adaptive sampling technique is used to reduce the computational time and improve the registration accuracy. Several experiments are performed to evaluate the proposed method. Experimental results show that the proposed method yields better performance compared to the conventional methods.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.48 no.8
• /
• pp.958-964
• /
• 1999

The distance in load parameter space to the closest saddle node bifurcation (CSNB) point provides the worst case power margin to voltage instability and the left eigenvector at CSNB identifies the most effective direction to steer the system to maximize voltage stability under contingency. This paper presents an improved direct method for computing CSNB: the order of nonlinear systems equations is reduced to about twice of the size of load flow equations in contrast to about three-times in Dobson's direct method; the initial guess for the direct method is computed efficiently and robustly by combined use of continuation power flow, a pair of multiple load flow solution with Lagrange interpolation. It is also shown that voltage stability may be enhanced significantly with shift of generations in the direction of the left eigenvector at CSNB.

• Journal of the Korean Mathematical Society
• /
• v.54 no.1
• /
• pp.215-225
• /
• 2017

In this paper, we study some equivalence relations between continuous frames in a Hilbert space ${\mathcal{H}}$. In particular, we seek two necessary and sufficient conditions under which two continuous frames are near. Moreover, we investigate a distance between continuous frames in order to acquire the closest and nearest tight continuous frame to a given continuous frame. Finally, we implement these results for shearlet and wavelet frames in two examples.

• The Journal of the Acoustical Society of Korea
• /
• v.19 no.3E
• /
• pp.19-24
• /
• 2000

The present research examined the contribution of sounds′ familiarity to auditory distance perception, while attempting to control the influences of unavoidable physical characteristics among sounds. Different vocal "styles" ("shouts", "whispers" and "a normal conversation") of man and woman were recorded digitally and presented from a stationary loudspeaker to blindfolded listeners in a semi anechoic chamber. Playback levels were adjusted to remove extraneous sound level cues. The results showed that the shouting voice was judged as appearing farthest, the whispering voice closest, and the conversational voice was intermediate. The findings suggested that the perception of auditory distance may be affected by past experience (or familiarity).