• 제어로봇시스템학회:학술대회논문집
• /
• 1997.10a
• /
• pp.1428-1431
• /
• 1997

This paper presents an efficient fault diagnosis methodology for lare chemical processes. The methodology is based on a two-tier strategy, When a falt occurs in a process, a top tier identifies the sector (process part or unit) that may contain the fault(s). Afterwards, a bottom tier or lower level evaluates the suspicious sector. The process modeling methodology based on functionality-behavior relations of process units, is proposed and utilized in the top-tier. This methodology models a target process as sequences of functions and variables and their relations. In the bottom tier, each sector has a dedicated diagostic module, which is tailored to the available information or models of the sector. For the sectors selected in the top-tier diagnosis, each diagnostic module is executed to identify the actual faults within the sector. Teh utility of the methodology is illustrated in the diagnosis of the CSTR with heat exchanger.

• Culinary science and hospitality research
• /
• v.23 no.6
• /
• pp.161-172
• /
• 2017

The purposes of this study were to examine if a decision making by a tourist sequentially or hierarchically occurs in a tourism destination and to test determinants that have an effect on both a sequential and non-sequential decision making. An instrument for the study was developed with three steps. A total of 420 and 380 questionnaire were collected respectively for the first two round surveys. For the third step, a pilot test was conducted with 30 respondents. And the data analysis utilized SPSS 18.0. A logistic regression analysis with variables of tourism activity and demography was employed to investigate the factors that affect a sequence of decision-making process. As an important result, the higher the age of the tourist in a tourism destination, the more conspicuous the consumption expenditure is made through the sequential decision-making process. Additionally, it is unreasonable to apply the premises and assumptions in extant consumer behavior to tourist behavior. The process of decision making by tourists in tourism areas is driven by either non-sequential or non-hierarchical decision-making process. More discussion and implications were provided.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2001.10a
• /
• pp.199-205
• /
• 2001

This paper describes the design methodology, manufacturing process, rebar tensile and bending properties. Braidtrusion is a direct Composite fabrication technique utilizing an in-line braiding and pultrusion process. The produced Composite rebar exhibits ductile stress-strain behavior similar to that of conventional steel bar. Various rebar diameters ranging from modeling scale(3m) to full-scale prototype of 9.5mm have been produced Glass Fiber Reinforced Plastics(GFRP) rebar were successfully fabricated at $\phi$8.5mm and $\phi$9.5mm nominal diameters of soild and hollow type using a braidtrusion process. Tensile and bending specimens were tested and compared with behavior of stress-strain of GFRP rebar and steel bar.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.12 no.4
• /
• pp.93-99
• /
• 2013

Parts and structures such as piston rod and knuckle joint for the use of hydraulic cylinder are often welded together in some fashion, usually due to cost and process effectiveness. Welding strongly affects the material by the process of heating and subsequent cooling as well as by the fusion process with additional filler material. Furthermore, a weld is usually far from being perfect, containing inclusions, pores, cavities, undercuts etc. As a consequence, fatigue failures appear in welded structures mostly at the welds rather than in the base metal, even if the latter contains notches. For this reason, fatigue analyses are of high practical interest for all welded structures under the action of cyclic loads. This paper describes the influence of welding parameters, material combinations and heat treatment on the fatigue behavior of welded cylinder rod. In addition, statistical characterization of stress-life response in weldment of hydraulic cylinder rod are presented.

• Journal of Powder Materials
• /
• v.8 no.2
• /
• pp.110-116
• /
• 2001

Abstract To investigate the effect of mechanical alloying process to thermoelectric properties of PbTe sintered body, Pb-Te mixed powder with Pb : Te : 1 : 1 composition was mechanically alloyed using tumbler-ball mill. Thermoelectric properties of the sintered body were evaluated by measuring of the Seebeck coefficient and specific electric resistivity from the room temperature to 50$0^{\circ}C$. Sintered body of only mechanically alloyed PbTe powder showed p-type behavior at the room temperature, and occurred type transition from p-type to n-type at about 30$0^{\circ}C$. PbTe sintered body which was fabricated using heat treated powder in $H_2$ atmosphere after mechanical alloying showed stable n-type behavior under 50$0^{\circ}C$. N-type PbTe sintered body fabricated by mechanical alloying process had 4 times higher power factor than that fabricated by the melt-crushing process. Application of a mechanical alloying process to fabricate of n-type PbTe thermoelectric material seemed to be useful to increase the power factor of PbTe sintered body.

• Journal of the Korean Society of Safety
• /
• v.26 no.5
• /
• pp.46-53
• /
• 2011

The risk assessment of thermal behavior and runaway reaction cased by an exothermic batch process in manufacture of the vinyl acetate resin are described in the present paper. The aim of the study was to evaluate the risk of runaway reaction with operating parameters such as a reaction inhibitor, reaction temperature and a mount of methanol charged in the vinyl acetate polymerization process. The experiments were performed by a sort of calorimetry with the Multimax reactor system as a screening tool to investigate runaway reaction. From the experimental results, it was found that we could occur the auto acceleration for reaction of raw materials with operating parameters over $65^{\circ}C$ of reaction temperature in the vinyl acetate polymerization process.

• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.11
• /
• pp.122-132
• /
• 1999

This study describes a dynamic model of the hydroforming process which is used for precision forming of sheet metals. To help the controller design for the control of the forming pressure needed for this process as well as to investigate the effect of system parameters on the dynamic behavior, dynamic modeling is performed with emphasis on hydraulic servo system which actuates the forming machine. Since the model contains several unknown parameters, these were estimated via a least square parameter identification method. Based upon the identified model, a series of simulations were performed for various operating conditions. The results were compared with those of the experiments to verify the validity of the proposed model. The comparison study shows that the proposed dynamic model can describe dynamic behavior of the forming pressure of the hydroforming process to desirable accuracy.

• Culinary science and hospitality research
• /
• v.22 no.6
• /
• pp.120-131
• /
• 2016

The purpose of this study was to examine the structural relationship between customers' perception of authenticity, justice, customer commitment, and customer behavior in franchise coffee shops. To test the hypotheses of the study, a total of 428 customers in Korea were considered in an empirical analysis using a two-step structural equation model (SEM) approach. In particular, employees' authenticity had relatively great influence on customers' continuous and affective commitment and their justice had greater influence on customers' normative commitment. Also, customers' continuous commitment, normative commitment, and affective commitment significantly influence customer participation behavior, while normative commitment and affective commitment have a significant effect customer citizenship behavior. Research thus far divided justice and authenticity into separate concepts and examined relation with customer commitment or behaviors but the present study put cognitive process of justice and emotional process of authenticity on the same line and evaluated their different influence on customer commitment and behaviors, thereby verifying that not justice perceived by customers induced desirable customer behaviors but authenticity they felt with their heart played a more superior role in customer commitment or behaviors. This means that authentic services rather than justice induce customers' positive behaviors.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.36 no.10
• /
• pp.1255-1260
• /
• 2012

The densification behavior of titanium powder in the direct powder rolling process was investigated. An analytical model for the roll-backlash phenomenon during this process was proposed to conduct a realistic finite element analysis. Furthermore, the roll-backlash was quantitatively analyzed, and the relative densities of the greenstrip along the rolling direction were precisely estimated. Finally, the slip and nip phenomena were identified by calculating the contact pressure and shear stress between the titanium powder and the roller in order to understand the densification behavior of the powder during the rolling process.

• The Journal of the Korea Contents Association
• /
• v.12 no.12
• /
• pp.126-134
• /
• 2012

The researchers of this study closely looked into the methods for cognitive-scientific approach to problems of marine design at a time when the overall values of marine cultures are acknowledged in full scale. To that end, the researchers analyzed the problems and problem-solving process for the initial approach to marine design. At the same time, the researchers made the matrix of the design-developmental directions by cognitive scientific approach. After selecting the subjects, the researchers collected verbal protocol and behavior protocol which were shown in the process of a designer's thinking. This was for the sake of protocol analysis which is the representative research technique of cognitive science. Based on the collected data, the researchers empirically analyzed the behavior patterns shown in the marine design process so as to develop the design behavior-graph pattern of designers in an objective and systematic way. The behavior graph was helpful for looking into the initial developmental directions of design and for predicting cognitive structure of designers. The researchers hope that this study will become a fundamental material for predicting cognitive directions of designer for planning and designing the marine design.