Search Results - "Cha, Ji Hwan"

Characteristics of Biogas Production from Organic Wastes Mixed at Optimal Ratios in an Anaerobic Co-Digestion Reactor by Song, Young-Ju, Oh, Kyung-Su, Lee, Beom, Pak, Dae-Won, Cha, Ji-Hwan, Park, Jun-Gyu

“…This study determined the optimal mixing ratio of food waste and livestock manure for efficient co-digestion of sewage sludge by applying the biochemical…”
Get full text

Microstructure and Tensile Properties of Diffusion Bonded Austenitic Fe-Base Alloys—Before and After Exposure to High Temperature Supercritical-CO2 by Kim, Sung Hwan, Cha, Ji-Hwan, Jang, Changheui, Sah, Injin

“…Austenitic Fe-base alloys, SS 316H and Alloy 800HT, were diffusion bonded for use in compact-type heat exchangers in supercritical-carbon dioxide (S-CO2)…”
Get full text

New stochastic models for preventive maintenance and maintenance optimization by Lee, Hyunju, Cha, Ji Hwan

“…•This paper provides a stochastic model for PM based on a generalized minimal repair process.•This paper studies the optimal preventive maintenance problem…”
Get full text

An extended model for optimal burn-in procedures by Cha, J.H.

“…In this paper, the problem of determining optimal burn-in time is considered under the general failure model. There are two types of failure in the general…”
Get full text

New shock models based on the generalized Polya process by Cha, Ji Hwan, Finkelstein, Maxim

“…•This paper studies shock models based on a new counting process of shocks.•The obtained results are interpreted based on the point process approach.•The…”
Get full text

Corrosion and creep behavior of a Ni-base alloy in supercritical-carbon dioxide environment at 650 °C by Kim, Sung Hwan, Cha, Ji-Hwan, Jang, Changheui

“…•Creep tests of Alloy 600 were conducted in S-CO2 environment at 650 °C (20 MPa).•Creep rupture lives were shorter in S-CO2 compared to air and CO2.•Tensile…”
Get full text

On optimal burn-in procedures - a generalized model by Cha, J.H.

“…Burn-in is a manufacturing technique that is intended to eliminate early failures. In this paper, burn-in procedures for a general failure model are…”
Get full text

Cr diffusion coating to improve the corrosion resistance of an ODS steel in super-critical carbon dioxide environment by Kim, Chaewon, Kim, Sung Hwan, Cha, Ji-Hwan, Jang, Changheui, Kim, Tae Kyu

“…The surface of oxide dispersion strengthened (ODS) steel was deposited with Cr by physical vapor deposition, followed by inter-diffusion heat treatment…”
Get full text

Rejuvenation of the Lower Eyelid and Midface with Deep Nasolabial Fat Lift in East Asians by Lee, Tae-Yul, Cha, Ji-Hwan, Ko, Han-Woong

“…Correcting infraorbital hollowness is an important procedure for midface rejuvenation. Sub-orbicularis oculi fat lift is a commonly used method. However,…”
Get full text

Optimal burn-in procedure for mixed populations based on the device degradation process history by Cha, Ji Hwan, Pulcini, Gianpaolo

“…•This paper proposes a new degradation history-based burn-in procedure.•The proposed procedure utilizes degradation process history of the item observed during…”
Get full text

Poisson generalized gamma process and its properties by Hwan Cha, Ji, Mercier, Sophie

“…Although the nonhomogeneous Poisson process has been intensively applied in practice, it has also its own limitations. In this paper, a new counting process…”
Get full text

Development of aluminide diffusion coatings on ODS ferritic-martensitic steel for corrosion resistance in high temperature super critical-carbon dioxide environment by Kim, Chaewon, Cha, Ji-Hwan, Kim, Sung Hwan, Jang, Changheui, Kim, Tae Kyu

“…[Display omitted] •Aluminide diffusion coating with Al or NiAl was applied on ODS-FM steel.•Both showed superior corrosion and carburization resistance in SCO2…”
Get full text

On a new age‐replacement policy for items with observed stochastic degradation by Finkelstein, Maxim, Cha, Ji Hwan, Levitin, Gregory

“…A new methodology for preventive maintenance of degrading items is discussed. It combines the classical age‐replacement strategy when a system is replaced…”
Get full text

Optimal Replacement of Heterogeneous Items With Minimal Repairs by Cha, Ji Hwan

“…In this paper, a new replacement policy for a deteriorating item from a mixed population is suggested. The item is randomly selected from a mixed population…”
Get full text

On optimal replacement of systems with failure rates described by a random jump process by Cha, Ji Hwan, Finkelstein, Maxim, Levitin, Gregory

“…Preventive maintenance (age replacement) of items operating in a random environment modeled by a Poisson shock process, resulting in random jump process in the…”
Get full text

On preventive maintenance under different assumptions on the failure/repair processes by Cha, Ji Hwan, Finkelstein, Maxim

“…We discuss models of preventive maintenance (PM) under different assumptions on the failure/repair processes. The main emphasis is on the PM modeling under the…”
Get full text

Optimal Long-Run Imperfect Maintenance With Asymptotic Virtual Age by Ji Hwan Cha, Finkelstein, Maxim

“…We consider imperfect, periodic preventive maintenance of items with increasing failure rates, and minimal repairs in-between. The imperfect maintenance is…”
Get full text

Effect of Minor Alloying Elements on the Oxidation Behavior of Ni-Base Alloys in a High-Temperature Steam Environment by Kim, Sung Hwan, Kim, Chaewon, Cha, Ji-Hwan, Jang, Changheui, Yoo, Young Soo

“…Model alloys based on Alloy 617 were fabricated with modified minor alloying elements for improvement in oxidation resistance in high-temperature steam…”
Get full text

Developing a Practical Tool for Predicting Wound Healing Outcomes of Patients with Diabetic Forefoot Ulcers: Focus on Vasculopathy and Infection by Moon, Kyung-Chul, Cha, Ji-Hwan, Han, Seung-Kyu, Son, Ji-Won

“…To develop a preliminary risk scoring system to predict the prognosis of patients with diabetic forefoot ulcers based on the severity of vasculopathy and…”
Get full text

Modeling Discrete Bivariate Data with Applications to Failure and Count Data by Lee, Hyunju, Cha, Ji Hwan, Pulcini, Gianpaolo

“…In this study, we propose a new class of flexible bivariate distributions for discrete random variables. The proposed class of distribution is based on the…”
Get full text