• Journal of the Korean Operations Research and Management Science Society
• /
• v.23 no.3
• /
• pp.49-62
• /
• 1998

In the ring loading problem, traffic demands are given for each pair of nodes in an undirected ring network with n nodes and a flow is routed in either of the two directions, clockwise and counter-clockwise. The load of a link is the sum of the flows routed through the link and the objective of the Problem is to minimize the maximum load on the ring. In the ring loading problem with integer demand splitting, each demand can be split between the two directions and the flow routed in each direction is restricted to integers. Recently, Vachani et al. ［INFORMS J. Computing 8 (1996) 235-242］ have developed an Ο(n$^3$) algorithm for solving this integer version of the ring loading problem and independently, Schrijver et al. ［to appear in SIAM J. Disc. Math.］ have presented an algorithm which solves the problem with ｛0,1｝ demands in Ο（n$^2$｜K｜ ) time where K denotes the index set of the origin-desㅇtination pairs of nodes having flow demands. In this paper, we develop an algorithm which solves the problem in Ο(n ｜K｜) time.

• Korean Management Science Review
• /
• v.18 no.2
• /
• pp.107-116
• /
• 2001

In the ring leading problem with demand splitting, traffic demands are given for each pair of nodes in an undirected ring network and a flow is routed in either of the two directions, clockwise and counter-clockwise. The load of a link is the sum of the flows routed through the link and the objective of the problem is to minimize the maximum link load on the ring. Recently, four different optimal a1gorithms have been developed for solving the problem. In this paper, we compare those algorithms in a single framework and conduct a computational study to evaluate the practical performance of those algorithms.

• Korean Journal of Crystallography
• /
• v.10 no.1
• /
• pp.66-70
• /
• 1999

The calix[4]arene molecule adopting the 1,3-alternate conformation forms a square cavity, and two pair phenyl rings lying above and below a least-square plane defined by the four bridging methylene groups in the calix[4]arene are widened upwards and downwards, respectively, from central axis, which leads to O1-O4=4.064 and O2-O3=3.864 . Two propyloxy groups are stabilized with all trans conformations, but the rather short azacrown ether chain with two oxygen atoms includes cis/trans conformations with O1-C35=2.906 . Therefore the cavity does not seem to be big enough to form a host-guest complex.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.02a
• /
• pp.315-315
• /
• 2011

The ring formation and electronic properties of furan adsorbed on graphene layers grown on 6H-SiC(0001) has been investigated using atomic force microscopy (AFM), near edge X-ray absorption fine structure (NEXAFS) spectra for the C K-edge, and high resolution photoemission spectroscopy (HRPES). Moreover, we observed that furan molecules adsorbed on graphene could be used for chemical functionalization via the lone pair of electrons on the oxygen group, allowing chemical doping. We also found that furan spontaneously formed rings with one of three different bonding configurations and the electronic properties of the ring formed by furan on graphene can be described using by AFM, NEXAFS and HRPES, respectively.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.27 no.4
• /
• pp.1-10
• /
• 2002

The ring routing and wavelength assignment problem arose in the planning of optical communication networks which use WDM rings. Traffic demands are given for each pair of nodes in an ring : each demand must be routed one of the two possible connections round the ring and the wavelength assignments must be made so that there are no conflicts : that is. no two connections whose routes share a link can be assigned the same wavelength along that link. The objective is to minimize the number of used wavelengths. We propose the local optimal routing for the problem and show that there always exists an optimal solution satisfying it. Furthermore we suggest a new lower bound for the problem and show that it is very efficient for the worst case example.

• Bulletin of the Korean Chemical Society
• /
• v.24 no.4
• /
• pp.431-436
• /
• 2003

Solvolytic rate constants at 25℃ are reported for solvolyses of cinnamyl bromide (1) in binary mixtures of water with acetone, ethanol, methanol, methanol-d, and 2,2,2-trifluoroethanol. Product selectivities are reported for solvolyses of 1 in aqueous ethanol and methanol. Rate ratios in solvents of the same $Y_{Br}$ value and different nucleophilicity provide measures of the minimum extent of nucleophilic solvent assistance (e.g. $[k_{40EW}/k_{97TFE}]$Y = 2.88, EW = ethanol-water). With use of the extended Grunwald-Winstein equation, the l and m values are similar to the values of 0.43 and 0.88 obtained for the solvolyses of 1 using the equation (see below) which includes a parameter (I) for solvation of aromatic rings. The magnitude of l and m values associated with a change of solvent composition predicts the $S_{N1}$ reaction mechanism rather than an $S_{N2}$ channel. Product selectivities (S), defined by S = [ether product]/[alcohol product]×[water]/[alcohol solvent] are related to four rate constants for reactions involving one molecule of solvent as nucleophile and another molecule of solvent as general base catalyst. A linear relationship between 1/S and molar ratio of solvent is derived theoretically and validated experimentally for solvolyses of the above substrates from water up 75% 1/S = $(k_{wa}/k_{aw})$([alcohol solvent]/[water]) + $k_{ww}/k_{aw}$ alcohol-water. The results are best explained by product formation from a “free” carbocation intermediate rather than from a solvent-separated ion pair.

• Journal of the Korean Society of Costume
• /
• v.61 no.9
• /
• pp.84-96
• /
• 2011

This paper investigates the formative features and the historical meaning of the Korean dress collection held in the Museum of Archaeology and Anthropology in Cambridge. The Museum holds a total of eleven items of koran dresses that were donated by two anthropologists in the first half of the twentieth century. Male dresses consist of a white cotton jacket (Jeogori), a under-vest (Deungbaeja) made of light wisteria rings, a headband (Manggeon) made of horsehair, a broad brimmed top hat (Gat) made of black horsehair gauze, an oilskin cover (Galmo) drawn over the hat in wet weather, and a hemispherical hat box (Gatjib). Female dresses comprise a pink silk jacket (Jeogori), a blue silk skirt (Chima) with pleats, a pair of woman's white cotton trousers (Sokgot), a black silk cap (Jobawi) decorated with pink tassels and imitation pearls, and a pair of green and magenta silk shoes (Danghye) with leather soles and metal rivets. Theses Korean dresses show what the western anthropologists had interests in. When collectors collect the folk objects, they thought much of the specificity of shape and material, the esthetic appreciation, and the representation of daily life. In terms of the value as the historical materials in the history of Korean dress, the under-vest of wisteria, the hat box, and the female dresses are worth paying attention to. The under-vest is one that was produced in earlier time among the remaining under-vests. The hat box represents that the hat belonged to the merchant classes. The female dress items show daily dresses worn by women of higher classes of the society in the 1920s.

• Wind and Structures
• /
• v.15 no.4
• /
• pp.331-343
• /
• 2012

Thunderstorm downbursts are responsible for numerous structural failures around the world. The wind characteristics in thunderstorm downbursts containing vortex rings differ with those in 'traditional' boundary layer winds (BLW). This paper initially performs an unsteady-state simulation of the flow structure in a downburst (modelled as a impinging jet with its diameter being $D_{jet}$) using a computational fluid dynamics (CFD) method, and then analyses the pressure distribution on a solar updraft tower (SUT) in the downburst. The pressure field shows agreement with other previous studies. An additional pair of low-pressure region and high-pressure region is observed due to a second vortex ring, besides a foregoing pair caused by a primary vortex ring. The evolutions of pressure coefficients at five orientations of two representative heights of the SUT in the downburst with time are investigated. Results show that pressure distribution changes over a wide range when the vortices are close to the SUT. Furthermore, the fluctuations of external static pressure distribution for the SUT case 1 (i.e., radial distance from a location to jet center x=$D_{jet}$) with height are more intense due to the down striking of the vortex flow compared to those for the SUT case 2 (x=$2D_{jet}$). The static wind loads at heights z/H higher than 0.3 will be negligible when the vortex ring is far away from the SUT. The inverted wind load cases will occur when vortex is passing through the SUT except on the side faces. This can induce complex dynamic response of the SUT.

• Journal of Sensor Science and Technology
• /
• v.26 no.2
• /
• pp.101-106
• /
• 2017

A novel intravenous (IV) infusion monitoring sensor is presented to measure the drop rate in the drip chamber of an IV infusion set. It is based on a capacitive proximity sensor and detects the variation of the longitudinal electric field induced by the drop falling into the drip chamber. Unlike the conventional capacitor sensor with two semi-cylindrical conductor plates, the proximity sensor for IV monitoring is composed of a pair of conductor rings which are mounted on the outer surface of the drip chamber with a specific gap between them. The characteristics of the proximity sensor for IV monitoring were investigated through three dimensional electrostatic simulations. It showed quite superior performances in comparison with the conventional capacitor sensor. Especially, the proposed proximity sensor exhibits consistent sensitivity regardless of its mounting position on the drip chamber, operates normally though the drip chamber is tilted and shows robustness to the changes of the drop size and the drip factor of the IV infusion set. Thus, the proximity sensor for IV monitoring is more suitable for use in actual environment of IV therapy compared with the conventional capacitor sensor.

• Journal of Veterinary Clinics
• /
• v.15 no.1
• /
• pp.188-192
• /
• 1998

A 3-month old female Holstein calf was presented with about a month history of intermittent dyspnea, exercise intolerance and cough despite antibiotic therapy. Auscultation revealed prominent inspiratory and exploratory crackles and wheezes over the causal cervical trachea which were heard equally over both side of the chest.4 modest amount of forced exercise caused severe respiratory distress with stertorous noise and occasional honkinglike cough. Pasteurella spp. was isolated on the nasal swabs and a hemogram showed mild leucocytosis with a mature neutrophilia and mild monocytosis. Lateral radiographs of the neck and thorax revealed a marked narrowing of the tracheal lumen extending from the level of the fifth cervical to the second thoracic vertebra, and the lung field was judged to be within normal limitsi except very mild peribronchial thickening. The hypertrophic non-union fractures of the first pair of ribs were noted with a well delineatedr redundant callus formations and also the completely healed fractures were found on the next seven pairs of ribs. A diagnosis of tracheal collapse was made, which is thought to be a traumatic origin.4 poor prognosis was given. The calf was euthanatized and necropsied. The tracheal rings from 19th to 41s1 were collapsed dorsoventrally. Histologically, there was no difference between the collapsed and normal areas of the tracheae except the folding mucosal layer in the collapsed area. This report details a case of tracheal collapse in a calli and the literature is reviewed.