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Wyszukujesz frazę "Kim, C." wg kryterium: Autor


Tytuł:
A mixed control chart adapted to the truncated life test based on the Weibull distribution
Autorzy:
Khan, N.
Aslam, M.
Kim, K.-J.
Jun, C. -H.
Powiązania:
https://bibliotekanauki.pl/articles/406432.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
life test
Weibull distribution
attribute chart
binomial distribution
average run length
Opis:
The design of a new mixed attribute control chart adapted to a truncated life test has been pre-sented. It was assumed that the lifetime of a product follows the Weibull distribution and the number of failures was observed using a truncated life test, where the test duration was specified as a fraction of the mean lifespan. The proposed control chart consists of two pairs of control limits based on a binomial distribution and one lower bound. The average run length of the chart was determined for various levels of shift constants and specified parameters. The efficiency of the chart is compared with an existing control chart in terms of the average run length. The application of the proposed chart is discussed with the aid of a simulation study.
Źródło:
Operations Research and Decisions; 2017, 27, 1; 43-55
2081-8858
2391-6060
Pojawia się w:
Operations Research and Decisions
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A queueing system with heterogeneous impatient customers and consumable additional items
Autorzy:
Baek, J.
Dudina, O.
Kim, C.
Powiązania:
https://bibliotekanauki.pl/articles/907646.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
marked Markovian arrival process
consumable additional items
phase type distribution
impatient customer
Markowski proces zgłoszeń
system kolejkowy
rozkład fazowy
klient niecierpliwy
Opis:
A single-server queueing system with a marked Markovian arrival process of heterogeneous customers is considered. Type-1 customers have limited preemptive priority over type-2 customers. There is an infinite buffer for type-2 customers and no buffer for type-1 customers. There is also a finite buffer (stock) for consumable additional items (semi-products, half-stocks, etc.) which arrive according to the Markovian arrival process. Service of a customer requires a fixed number of consumable additional items depending on the type of the customer. The service time has a phase-type distribution depending on the type of the customer. Customers in the buffer are impatient and may leave the system without service after an exponentially distributed amount of waiting time. Aiming to minimize the loss probability of type-1 customers and maximize throughput of the system, a threshold strategy of admission to service of type-2 customers is offered. Service of type-2 customer can start only if the server is idle and the number of consumable additional items in the stock exceeds the fixed threshold. Stationary distributions of the system states and the waiting time are computed. In the numerical example, we show some interesting effects and illustrate a possibility of application of the presented results for solution of optimization problems.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2017, 27, 2; 367-384
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Study Of The Die Roll Height Of SHP-1 And SCP-1 Materials In The Fine Blanking Process
Badanie wysokości deformacji krawędzi wycinanych elementów ze stali SHP-1 i SCP-1 procesie wykrawania
Autorzy:
Lee, C. K.
Kim, Y. C.
Powiązania:
https://bibliotekanauki.pl/articles/356499.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
die roll
fine blanking
SCP-1
share speed
SHP-1
v-rings
krawędzie
wykrawanie
szybkość działania
deformacja
Opis:
The height of the die roll, the distance of the V-ring, and the shear rate were varied with the aim of investigating the effects of the applied changes on the fine blanking line in a cold-rolled and a pickled steel sheet, referred to as SCP-1 and SHP-1, respectively. Both materials consisted primarily of a ferrite phase with small amounts of impurities including F, Mn, and Cr. The distance was found to be a very important factor in controlling the shear of the V-ring in the fine blanking process. When the position of the V-ring was set at distances of 1.5 mm and 2 mm, the die roll height increased with increasing shear speeds from 6.4 m/min to 10 and 16 m/min. Analysis of the influence of the shear rate revealed that low rates resulted in the lowest die roll heights since the flow of material was effectively inhibited.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1397-1402
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A study of the local entropy generation rate in a porous media burner
Autorzy:
Mohammadi, I.
Esfahani, J. A.
Kim, K. C.
Powiązania:
https://bibliotekanauki.pl/articles/38597672.pdf
Data publikacji:
2020
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
porous media burner
chemical kinetics
volumetric heat transfer
axisymmetric combustion
local entropy generation
excess air ratio
Opis:
In this paper, the work and performance of the premixed methane-air porous axisymmetrical burner have firstly been simulated numerically using the CFD tools. For this purpose the set of governing equations has been enriched by an additional energy equation in porous solid, and the chemical species transport has been extended onto the multi-step mechanism (GRI-2-11). This numerical model has been verified on the base of available benchmark experiments. Next, we have studied the local entropy generation problem taking into account not only classical contributions like viscous and turbulent dissipation but also, the porous combustion of gases. The results showed that the greatest portion of entropy generation in the porous medium burner is related to chemical reactions, followed by heat transfer, mass diffusion (mixing) and friction (viscous dissipation), respectively. According to the results, as the excess air ratio increases, the local entropy generation rate due to heat transfer and friction increases and the local entropy generation rate due to chemical reactions is decreased. Also, by increasing the volumetric heat transfer coefficient, the local entropy generation rate due to heat transfer decreases and the local entropy generation rate due to friction and chemical reactions increases. Also, the local entropy generation rate due to mixing does not show a significant change with the changing excess air ratio and volumetric heat transfer coefficient.
Źródło:
Archives of Mechanics; 2020, 72, 3; 257-279
0373-2029
Pojawia się w:
Archives of Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Study on Changes in Thickness of STS304 Material in the Progressive Drawing Process
Autorzy:
Lee, C. K.
Kim, Y. C.
Powiązania:
https://bibliotekanauki.pl/articles/356710.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
body thickness
drawing
flange thickness
corner roundness
material thickness
Opis:
In the drawing process, the roundness of corners in the punch and the die are very important factors in determining the thicknesses of the product. The results clearly revealed that the thickness of a flange was increased and the thickness of body parts reduced when the roundness of the die entrance was small. The material thickness of the top part was decreased when the corner roundness of the punch was large. The smooth inflow of materials was found to have a significant effect on the thickness during the post-process. The compressive strength of STS 304 material exhibited a higher value compared with other processing methods. Moreover, we clearly observed the corner roundness of the punch and the die to be a very important factor for STS 304 materials.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1319-1323
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Study On Dispersion Stability Of Nickel Nanoparticles Synthesized By Wire Explosion In Liquid Media
Badanie stabilności dyspersji nanocząstek niklu wytworzonych metodą WEP w ciekłym medium
Autorzy:
Kim, C. K.
Lee, G.-J.
Lee, M. K.
Rhee, C. K.
Powiązania:
https://bibliotekanauki.pl/articles/356909.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
nickel nanofluid
pulsed wire evaporation
surfactant
zeta potential
dispersion stability
nanocząstka niklu
środek powierzchniowo czynny
stabilność dyspersji
potencjał zeta
dyspersja
Opis:
In this study, nickel nanoparticles were synthesized in ethanol using portable pulsed wire evaporation, which is a one-step physical method. From transmission electron microscopy images, it was found that the Ni nanoparticles exhibited a spherical shape with an average diameter of 7.3 nm. To prevent aggregation of the nickel nanoparticles, a polymer surfactant was added into the ethanol before the synthesis of nickel nanoparticles, and adsorbed on the freshly synthesized nickel nanoparticles during the wire explosion. The dispersion stability of the prepared nickel nanofluids was investigated by zeta-potential analyzer and Turbiscan optical analyzer. As a result, the optimum concentration of polymer surfactant to be added was suggested for the maximized dispersion stability of the nickel nanofluids.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1379-1382
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A study on the development of a new grinding processes for high-lead ball screw nuts
Autorzy:
Choi, Ch.
Ha, Y.
Kim, H.
Lee, C.
Powiązania:
https://bibliotekanauki.pl/articles/99599.pdf
Data publikacji:
2010
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
high-lead ball screw nuts
new grinding process
surface roughness
Opis:
This paper proposes a method that machines the race of high-lead ball screw nuts, which is difficult to machine using the existing geometrical machining method, without any interferences and changes in its load rating in order to perform the high-speed in ball screws. This study calculates the inclination angle of the axis of the grinding stone for avoiding the contact of the axis to the inner diamete of the nut and determines the shape of the grinding stone through changing the inclination angle and dressing curvature determined in a dressing device Then, the grinding condition will be determined by measuring the shape meter of the screw race for solving the problem. Also, the surface roughness of the grinded surface was measured using a surface roughness tester, and check with applying a grinding process of product not being high-lead ball screw.
Źródło:
Journal of Machine Engineering; 2010, 10, 1; 50-57
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Allometric scaling of marbofloxacin pharmacokinetics: a retrospective analysis
Autorzy:
Yohannes, S.
Hossain, M.A.
Kim, J.Y.
Lee, S.J.
Kwak, D.M.
Suh, J.W.
Park, S.C.
Powiązania:
https://bibliotekanauki.pl/articles/31939.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
The association between physiologically dependent pharmacokinetic parameters (CLB, T1/2β, Vdss) of marbofloxacin and body weight was studied in eight animal species based on allometric equation Y = aWb, where ‘Y’ is the pharmacokinetic parameter, ‘W’ is body weight, ‘a’ is allometric coefficient (intercept) and ‘b’ is the exponent that describes relation between pharmacokinetic parameter and body weight. The body clearance of marbofloxacin has shown significant (P<0.0001) relation with size (Bwt) in various animal species. However, half-life and volume of distribution were not in association with body weight. Although half-life and volume of distribution were not in a good correlation with body weight, statistically significant association between the body clearance and body weight suggests validity of allometric scaling for predicting pharmacokinetic parameters of marbofloxacin in animal species that have not been studied yet. However further study considering large sample size and other parameters influencing pharmacokinetics of marbofloxacin is recommended.
Źródło:
Polish Journal of Veterinary Sciences; 2014, 17, 1
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Aluminum Nitride Formation From Aluminum Oxide/Phenol Resin Solid-Gel Mixture By Carbothermal Reduction Nitridation Method
Wytwarzanie azotku aluminium z żelowej mieszaniny tlenku aluminium z żywicą fenolową metodą azotowania podczas carbotermicznej redukcji
Autorzy:
Mylinh, D. T.
Yoon, D. H.
Kim, C.-Y.
Powiązania:
https://bibliotekanauki.pl/articles/356779.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aluminum nitride
powder
carbothermal reduction
nitridation
solid-gel mixture
azotek aluminium
proszek
redukcja karbotermiczna
azotowanie
żelowa mieszanina
Opis:
Hexagonal and cubic crystalline aluminum nitride (AlN) particles were successfully synthesized using phenol resin and alpha aluminum oxide (α-Al2O3) as precursors through new solid-gel mixture and carbothermal reduction nitridaton (CRN) process with molar ratio of C/Al2O3 = 3. The effect of reaction temperature on the decomposition of phenol resin and synthesis of hexagonal and cubic AlN were investigated and the reaction mechanism was also discussed. The results showed that α-Al2O3 powder in homogeneous solid-gel precursor was easily nitrided to yield AlN powder during the carbothermal reduction nitridation process. The reaction temperature needed for a complete conversion for the precursor was about 1700°C, which much lower than that when using α-Al2O3 and carbon black as starting materials. To our knowledge, phenol resin is the first time to be used for synthesizing AlN powder via carbothermal reduction and nitridation method, which would be an efficient, economical, cheap assistant reagent for large scale synthesis of AlN powder.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1551-1555
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Analysis Of Stress Intensity Factor Due To Normal Stress For A Cracked Plate Reinforced With A Sheet By Seam Welding
Analiza współczynnika intensywności naprężeń wynikających z prostopadłego naprężenia dla pękniętej płyty wzmocnionej płytą przyspawaną szwem
Autorzy:
Kim, O.-H.
Kim, Y. C.
Powiązania:
https://bibliotekanauki.pl/articles/352434.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
stress intensity factor
seam welding
singular integral equation
reinforcement effect
współczynnik intensywności naprężeń
spawanie
efekt wzmacniający
Opis:
It is essential in damage tolerance design to determine the stress intensity factor theoretically. The stress intensity factor for a cracked plate that is reinforced with a sheet by seam welding is determined theoretically and plotted as function of the seam welding location and stiffness ratio. The singular integral equation is derived based on the compatibility condition between the cracked plate and the reinforcement plate, and it is solved by means of Erdogan and Gupta‘s method. The theory is verified by comparing the results of the present analysis with those of a numerical analysis. The results from the present analysis show that the reinforcement effect improves as the welding line is situated closer to the crack and as the stiffness ratio of the cracked plate and the reinforcement plate increases.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1441-1444
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An analysis on the thermal characteristics according to the viscosity of bearing lubricant and the cooling condition for the high speed motor spindle
Autorzy:
Choi, D. B.
Lee, J. J.
Kim, S. T.
Kwon, H. D.
Kim, C. Y.
Powiązania:
https://bibliotekanauki.pl/articles/1429194.pdf
Data publikacji:
2008
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
high speed motor spindle
thermal displacement cooling condition
lubricant viscosity
Opis:
Thermal displacement of the high speed machine tools has a large influence on machining accuracy. The high speed motor spindle with many heat sources is widely used for the high speed machine tools recently. The important problem in this spindle is to reduce and minimize the thermal effects by motor and bearings. This paper presents the analysis on thermal characteristics for high speed motor spindle system with oil-air lubricated angular contact ceramic ball bearings and built-in motor. An analysis on the thermal characteristics of spindle is performed according to the cooling conditions and the viscosity of bearing lubricants by using finite element method. This results can be applied to the design and manufacturing for the high speed motor spindle.
Źródło:
Journal of Machine Engineering; 2008, 8, 4; 88-98
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of an MMAP/PH1, PH2/N/∞ queueing system operating in a random environment
Autorzy:
Kim, C.
Dudin, A.
Dudin, S.
Dudina, O.
Powiązania:
https://bibliotekanauki.pl/articles/330607.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
random environment
marked Markovian arrival process
phase type distribution
Laplace–Stieltjes transform
rozkład fazowy
transformata Laplace'a-Stieltjesa
system operacyjny
system kolejkowy
Opis:
A multi-server queueing system with two types of customers and an infinite buffer operating in a random environment as a model of a contact center is investigated. The arrival flow of customers is described by a marked Markovian arrival process. Type 1 customers have a non-preemptive priority over type 2 customers and can leave the buffer due to a lack of service. The service times of different type customers have a phase-type distribution with different parameters. To facilitate the investigation of the system we use a generalized phase-type service time distribution. The criterion of ergodicity for a multi-dimensional Markov chain describing the behavior of the system and the algorithm for computation of its steady-state distribution are outlined. Some key performance measures are calculated. The Laplace–Stieltjes transforms of the sojourn and waiting time distributions of priority and non-priority customers are derived. A numerical example illustrating the importance of taking into account the correlation in the arrival process is presented.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2014, 24, 3; 485-501
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biological Evaluation of Anodized Biodegradable Magnesium-Calcium Alloys
Autorzy:
Kim, J.
Lee, J.
Lee, K.
Park, S.
Lim, H.
Park, C.
Bae, J.
Yun, K.
Powiązania:
https://bibliotekanauki.pl/articles/1398763.pdf
Data publikacji:
2016-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.85.jj
87.85.J-
Opis:
The objective of this study was to evaluate the biocompatibility of studied binary magnesium-calcium (Mg-Ca) alloys for biodegradable intraosseous implants. Mg is necessary for health and is a non-toxic biodegradable material that decomposes naturally in the body. Nevertheless, Mg has been implicated in problems including diminished physical properties and corrosion resistance when degradation is too rapid prior to bone healing. This study has explored the effect of Ca on the corrosion resistance and biological evaluation after anodizing treatment with different contents of Ca alloy. Binary Mg-0.5Ca, Mg-1Ca and Mg-5Ca alloys were prepared by the casting method under an argon atmosphere and cut into disc-shaped pieces. Pure Mg alloy was used as the control. Anodic oxidation was performed for 15 minutes at a voltage of 120 V using an electrolyte solution containing Ca gluconate, sodium hexametaphosphate, and sodium hydroxide at room temperature. Corrosion resistance was analyzed using a corrosion tester. After a hydrogen evolution test, the surface pattern and phase changes were observed on a scanning electron microscop (SEM) and energy dispersive spectroscop (EDS). Microscopic evaluation of the adhesion and cell biological functions of Mg was conducted by observing the response of human fetal osteoblastic 1.19 cells with regard to changes in surface film properties, depending on the amount of Ca. Our results support the view that in Mg-xCa alloys (x=0.5, 1, 5 wt.%) treated using anodic oxidation, the increasing Ca content controls the rate of decomposition and improves corrosion resistance.
Źródło:
Acta Physica Polonica A; 2016, 129, 4; 728-735
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bringing Kano’s perspective to AHP: the 2D-AHP decision model
Autorzy:
Jung, U.
Yim, S.
Lim, S.
Kim, C.
Powiązania:
https://bibliotekanauki.pl/articles/407247.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
analytic hierarchy process (AHP)
Kano model
hybrid model
multicriteria decision making
two dimension perspective
Opis:
AHP and the Kano model are such prevalent TQM tools that it may be surprising that a true hybrid decision-making model has so far eluded researchers. The quest for a hybrid approach is complicated by the differing output perspective of each model, namely discrete ranking (AHP) versus a multi-dimensional picture (Kano). This paper presents a hybrid model of AHP and Kano model, so called two-dimension AHP (2D-AHP). This paper first compares the two approaches and justifies a hybrid model based on a simple conceit drawn from the Kano perspective: given a decision hierarchy, child and parent elements can exhibit multi-dimension relationships under different circumstances. Based on this premise, the authors construct a hybrid two-dimension AHP model whereby a functionaldysfunctional question-pair technique is incorporated into a traditional AHP framework. Using the proposed hybrid model, this paper provides a practical test case of its implementation. The 2D-AHP approach revealed important evaluation variances obscured through AHP, while a survey study confirmed that the 2D-AHP approach is both feasible and preferred in some respects by respondents. Although there have been rich research efforts to combine AHP and Kano model, most of them is simply about a series of individual usage of each methodology. On the other hand, the type of hybridization between AHP and Kano model in this paper is quite unique in terms of the two dimensional perspective. The model provides a general approach with application possibilities far beyond the scope of the test case and its problem structure, and so calls for application and validation in new cases.
Źródło:
Management and Production Engineering Review; 2016, 7, 4; 16-26
2080-8208
2082-1344
Pojawia się w:
Management and Production Engineering Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Carbon Co-Deposition During Gas Reduction of Water-Atomized Fe-Cr-Mo Powder
Autorzy:
Ali, B.
Choi, S. H.
Seo, S. J.
Maeng, D. Y.
Lee, C. G.
Kim, T. S.
Park, K. T.
Powiązania:
https://bibliotekanauki.pl/articles/352709.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
water atomization
Fe-based powder
oxide reduction
powder metallurgy
sinter-hardening alloys
Opis:
The water atomization of iron powder with a composition of Fe-3Cr-0.5Mo (wt.%) at 1600°C and 150 bar creates an oxide layer, which in this study was reduced using a mixture of methane (CH4) and argon (Ar) gas. The lowest oxygen content was achieved with a 100 cc/min flow rate of CH4, but this also resulted in a co-deposition of carbon due to the cracking of CH4. This carbon can be used directly to create high-quality, sinter hardenable steel, thereby eliminating the need for an additional mixing step prior to sintering. An exponential relationship was found to exist between the CH4 gas flow rate and carbon content of the powder, meaning that its composition can be easily controlled to suit a variety of different applications.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1119-1124
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł

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