• Journal of Information Technology Services
• /
• v.10 no.2
• /
• pp.247-257
• /
• 2011

In this paper, we propose a multiple-disseminators determining mechanism for Efficient Code Dissemination with low-delay(ECoDi) for wireless sensor networks (WSN). Code dissemination is in the spotlight as an important research issue since sensor nodes are necessary for updating new software remotely or fixing bugs dynamically. In particular, the time factor for code dissemination is the most important factor in order that the normal operation of nodes can be continuously performed as soon as finishing the dissemination. For this factor, ECoDi determines the set of disseminators through regression analysis based on the size of distributed code and the time of past unicasts and broadcasts. Then it transmits the entire code as a unicast to multiple disseminators, and the disseminators broadcast the code to the remaining neighbor nodes. Performance results on a testbed show that ECoDi reduces dissemination time significantly compared to a conventional scheme.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2001.04a
• /
• pp.321-326
• /
• 2001

In the present study, $Si_3N_4-SiC$ ceramic composites that contained up to 20 wt% of dispersed SiC particles were fabricated via hot-pressing with an oxynitride glass. The microstructure, the mechanical properties, and the cutting performance of resulting ceramic composites were investigated. By fixing the composition as $Si_3N_4-20$ wt% SiC, the effect of sintering time on the microstructure, the mechanical properties, and the cutting performance were also investigated. For machining of gray cast i개n, the tool life increases with increasing the amount of SiC content in the composites; The tool life also increased with increasing the sintering time. The tool life of the home-made cutting tools was very close to that of commercial $Si_3N_4$ cutting tool. The superior cutting performance of $Si_3N_4-SiC$ ceramic cutting tools suggests the possibility to be a new ceramic tool material.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.37 no.4
• /
• pp.126-133
• /
• 2014

This paper addresses order-lot pegging issues in the supply chain of a semiconductor business. In such a semiconductor business (memory or system LSI) order-lot pegging issues are critical to achieving the goal of ATP (Available to Promise) and on-time production and delivery. However existing pegging system and researches do not consider capacity limit on bottleneck steps. This paper presents an order-lot pegging algorithm for assigning a lot to an order considering quality constraints of each lot and capacity of bottleneck steps along the entire FAB. As a result, a quick and accurate response can be provided to customer order enquiries and pegged lot lists for each promised orders can be shown transparently and short or late orders can be detected before fixing the order.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1996.04a
• /
• pp.14-18
• /
• 1996

From the experimental study of Wire-Cut EDM of die-material(SKD-11), machining characteristics such as machining rate, surface roughness and hardness have been observed and evaluated under the conditions varing pulse on time, pulse off time, peak voltage after fixing other conditions. It was found that various operating conditions have significant influences on machining rate, surface roughness. Hardness of workpiece was unaffected by operating conditions.

• Journal of Korea Water Resources Association
• /
• v.33 no.S1
• /
• pp.37-47
• /
• 2000

The method of delays is widely used for reconstruction chaotic attractors from experimental observations. Many studies have used a fixed delay time ${\tau}_d$ as the embedding dimension m is increased, but this is not necessarily the best choice for obtaining good convergence of the correlation dimension. Recently, some researchers have suggested that it is better to fix the delay time window ${\tau}_w$ instead. Unfortunately, ${\tau}_w$ cannot be estimated using either the autocorrelation function or the mutual information, and no standard procedure for estimating ${\tau}_w$ has yet emerged. However, a new technique, called the C-C method, can be used to estimate either ${\tau}_d\;or\;{\tau}_w$. Using this method, we show that, for small data sets, fixing ${\tau}_w$, rather than ${\tau}_d$, does indeed lead to a more rapid convergence of the correlation dimension as the embedding dimension m in increased.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.17 no.2
• /
• pp.23-29
• /
• 2008

This study analyzes the rolled circular rod strip with radius of loom and length of 350cm by using finite element analysis. The material strength and its durability of the rolled strip can be predicted through this study. As the penetration tolerance by contact decreases, the contact rigidity of strip increases. As the contact rigidity becomes the highest at the elapsed time of 1.2 second, the contact stress becomes the lowest. On the contrary, von-Mises stress becomes highest at this time. The total deformation on strip increases from the upper part of strip at the position near to rotating roll to the lower part of strip at the position near to fixing roll.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2000.05a
• /
• pp.37-47
• /
• 2000

The method of delays is widely used fur reconstructing chaotic attractors from experimental observations. Many studies have used a fixed delay time ${\tau}_d$ as the embedding dimension m is increased, but this is not necessarily the best choice for obtaining good convergence of the correlation dimension. Recently, some researchers have suggested that it is better to fix the delay time window ${\tau}_w$ instead. Unfortunately, ${\tau}_w$ cannot be estimated using either the autocorrelation function or the mutual information, and no standard procedure for estimating ${\tau}_w$has yet emerged. However, a new technique, called the C-C method, can be used to estimate either ${\tau}_d{\;}or{\;}{\tau}_w$. Using this method, we show that, for small data sets, fixing ${\tau}_w$, rather than ${\tau}_d$, does indeed lead to a more rapid convergence of the correlation dimension as the embedding dimension m is increased.

• Journal of Chest Surgery
• /
• v.55 no.3
• /
• pp.246-249
• /
• 2022

Recurrent pectus excavatum (PE) after a Ravitch operation is not uncommon. Extensive costal cartilage resection from the previous Ravitch procedure can lead to an irregular, unstable chest wall depressions with a varying degree of deformity. The optimal approach to cover the chest wall defect and remodel the deformity, remains unknown. We report the case of a 27-year-old woman seeking surgery for the third time for recurrent PE. The patient presented with 2-time recurrent pectus excavatum following a failed Ravitch procedure and subsequent pectus bar repair. The entire chest wall reconstruction and remodeling entailed covering the chest wall defect with 2 titanium plates across both sides of the rib cage, and lifting and fixing the depressed chest wall with 2 parallel pectus bars.

• 제어로봇시스템학회:학술대회논문집
• /
• 1999.10a
• /
• pp.244-247
• /
• 1999

This paper presents a methodology of the technique for controlling DC motor drive by implementation of 2-quadrant operating mode which can ensure the torque controlling and speed with response time less than 2 seconds at all loading conditions. By implementation of BRM technique, energy is fed with definite values of BRM 256 bits, with different patterns of high accuracy, and fixing scan time at 0.667 ms, the ripple is less than 1%, thus high efficiency can be achieved, from the consequence of the accuracy of energy feeding at low current. The stability of the whole system can be determined from circle criterion by root locus method . The instant reverse direction of rotation can be done by decreasing the energy to the lowest level while motor is running with no load and variable load at the speed about 100-120 rpm and 50-60 rpm.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.22 no.4
• /
• pp.258-267
• /
• 2020

The agrivoltaic can produce electricity and grow crops on fields at the same time. It is necessary to analyze the cultivation environment and evaluate the crop productivity under agrivoltaic because the shading point changes according to structure of agrivoltaic and sun's position. Two types of "fixing" and "tracing" agrivoltaic were installed, and a rice cultivation experiment was conducted in the fields under each agrivoltaic and without shading (control). "Hyunpoombyeo" was transplanted on June 7, 2019, and grown with fertilization of 9.0-4.5-5.7 kg/10a (N-P-K). Fifteen weather stations were installed under each agrivoltaic to measure solar radiation and temperature, and yield and yield-related elements were investigated by points. The accumulated solar radiation during the rice growing season in fixing was no much difference between points, and that in tracing was much difference between points. However, the average solar radiations of two agrivoltaics were similar. The mean temperature, yield, and yield-related elements showed a significant difference for the shading rate, and decreased with increasing the shading rate except ripening grain rate and 1000 grain weight of fixing agrivoltaic. In the relationship between shading rate and yield, fixing and tracing were fitted to a logistic equation and a simple linear equation, respectively, and showed a high correlation (tracing: R2 = 0.62, fixing: R2 = 0.73). The shading rate variation by point for two types was large despite similar yield variation. Thus, it needs to be more closely examined the relationship of the shading rate for a specific period rather than the shading rate during the whole growing season.