• International conference on construction engineering and project management
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• 2013.01a
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• pp.509-512
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• 2013

An inappropriate space zoning plan causes the unnecessary transportation of construction material and equipment among work areas and increases the disorder of work space. Space zoning is an essential operation management technique which contributes to reduce the process and/or operation idle-time. This paper introduces a method that computes the idle-times between construction operations (or processes) by using Web-CYCLONE. It allows computing with idle-times that affect the construction productivity. Using the idle time between operations and between processes, it computes the optimal number of zones and finds the optimal combination of zones that minimize the idle times. The method contributes to minimize the idle times relative to the operation schedule using complete enumeration. This paper presents the system prototype in detail. A case study is presented to demonstrate the system and verifies the validity of the model. It allows a project manager to establish space zoning plan that effectively segregates a project into optimal number of construction zones and to assign the constrained resources (e.g., laborer, equipment).

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.4
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• pp.169-176
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• 2017

This paper presents research on low-voltage microgrids to maintain a continuous power supply to critical loads on grid-connected islands in Korea. The low-voltage microgrids of this paper focused on that changes public office buildings into uninterrupted microgrids by autonomous operation. For this, a microgrid controller (MGC) and a power conditioning system (PCS) that allow a seamless transfer between grid-connected and grid-isolated operation are proposed. The proposed PCS operates with a silicon controlled rectifier (SCR) switch and employs a simple structure. It supplies power continuously without operators through a coordinated operation between MGC and PCS. In addition, proposed MG has a schedule operation for minimizing electricity charges and provides ancillary services that enable the utilization of resources according to the operation purpose of utility distribution networks. To demonstrate the uninterrupted low-voltage microgrid proposed in this study, a microgrid was implemented and tested in a public office building in Anjwa Island, Jeollanam-do in Korea. A seamless, autonomous operation history, despite system disturbances, was obtained through a long-term demonstration of operation. The results showed that the proposed microgrid technology can be used to achieve energy resilience in grid-connected island areas.

• Proceedings of the Korean Society for Quality Management Conference
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• 2004.04a
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• pp.513-516
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• 2004

Evolutionary operation is useful to improve on-line full-scale manufacturing processes by systematically changing the levels of the process variables while meeting production schedule. Evolutionary operation was developed using two or three process variables for process operators who are not good at statistics. Recently, when a product is developed, it is very important for the engineers to make the production line stable as soon as possible. And there are many causes which have influences to the product performance. This paper presents an evolutionary operation procedure with many process variables using saturated two level fractional factorial designs including Plackett-Burman design.

• Korean Journal of Construction Engineering and Management
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• v.5 no.2 s.18
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• pp.123-135
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• 2004

Construction accident have been increasing in despite of safety management activities and education in construction site. This study surveyed safety organization, education, safety management, scheduling, safety checklist with construction firms in order to grasp the actual condition. A improved method is suggested that safety checklist is supplemented with various safety materials and then stored as database. Furthermore, safety checklists are connected and operated with schedule in ender to more efficiently prevent construction accidents.

• Journal of Korean Academy of Nursing
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• v.23 no.1
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• pp.68-89
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• 1993

This study was conducted to develop a model of a fee schedule for nursing services.'Regardless of the demand for skilled and professional nursing service today, the Korean health insurance system does not furnish a chapter for the nursing service fee schedule. A nation-wide survey of hospital nursing service fee schedules was to provide practical and realistic data about how the variety of nursing services are being charged. From September 1990 to April 1991, data from the fee schedule used by twenty hospitals located in eight large cities which are designated large medical regions in the Korea Health Care and Patient Referral System were collected. Nursing services and the fees charged for them were analyzed. The nursing services were subjected to a secondary analysis with referrence to reports on “nursing services to be charged in Korea”. The total number of nursing services recommended by the literatures was 177 : finally 141 types of nursing services were selected by investigator as chargable nursing services. In addition, data on managerial characteristics of the hospitals were collected to discover influential variables for a nursing fee schedule model. Under the assumption that all the managerial characteristics of the hospitals influenced the fee schedule, the following model was tested : Fee of nursing services (C) = f(A₁, A₂, A₃, A₄, A/sub 5/, A/sub 6/, A/sub 7/, A/sub 8/,) When, A₁ = number of nurses A₂ = the first salary of a nurse educated in a four year A₃ = scale of nursing management division A₄ = location of the hospital A/sub 5/ = the type of hospital management (profit / non-profit) A/sub 6/ = number of hospital beds A/sub 7/ = years of hospital operation A/sub 8/ = number and kinds of clinical divisions The results showed that the model should be built as follows : C = f (A₁, A/sub 4/, A/sub 5/) Each nursing service was applied to the fee schedule with consideration for the professional level and time-taken to provide the services. Detailed fee schedules were presented in the related tables. Of the 141 kinds of nursing services, 24.8% were chargeble to the Korea Health Insurance, 32.6％ of the nursing services were being paid directly by the patienty. The rest of nursing services (42.6％) were not being charged to any source. It was recommened that the Korea Health Insurance Reimbursement system should add a classification system for nursing services that can be used in the national health care program. Further study is needed about how to include 32.6% of the nursing services now being paid for directly by the patients in the health insurance system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.04a
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• pp.359-363
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• 1992

As the demands of manufacturing automation is increasing, lots of efforts are devoted to the applications of Computer Integrated Manufacturing(CIM) concept in manufacturing shop floor. A workstation is a computer which controls differnet machines in the low level of factory(shop floor). A workstation can be utilized efficiently to enhance the coopetative work of machines. A scheduler is a component program in a workstation and it controls the operation of machines according to a fixed plan. A scheme for the scheduler has been developed for selected machines and software has been made. The fixed plan is stored in a schedule file which keeps machine names, communications methods, information for communications and time for the usages, etc. The scheduler carries out its role by the information in the schedule file. Although the developed software has some Iimitations, the test results show that the scheduler can be applied easily to the automation of the low level of factory.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.45
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• pp.165-180
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• 1998

To make a scheduling for minimizing the tardiness of delivery, we present an efficient heuristic algorithm for job-shop scheduling problems with due dates. The SDME(Slack Degree Modified Exchange) algorithm, which is the proposed heuristic algorithm, carries out the operation in two phases. In the phase 1, a dispatching rule is employed to generate an active or non-delay initial schedule. In the phase 2, tasks selected from a predetermined set of promising target operations in the initial schedule are tested to ascertain whether, by left-shifting their start times and rearranging some subset of the remaining operations, one can reduce the total tardiness. In the numerical example, the results indicate that the proposed SDME algorithm is capable of yielding notable reductions in the total tardiness for practical size problems.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.12
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• pp.597-602
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• 2005

The introduction of competition in electricity market emphasizes the importance of sufficient transmission capacities to guarantee various electricity transactions. Therefore, when dispatch scheduling, transmission security constraints should be considered for the economic and stable electric power system operation. In this paper, we propose an optimal dispatch scheduling algorithm incorporating transmission security constraints. For solving these constraints, the dispatch scheduling problem is decomposed into a master problem to calculate a general optimal power flow (OPF) without transmission security constraints and several subproblems to inspect the feasibility of OPF solution under various transmission line contingencies. If a dispatch schedule given by the master problem violates transmission security constraints, then an additional constraint is imposed to the master problem. Through these iteration processes between the master problem and subproblems, an optimal dispatch schedule reflecting the post-contingency rescheduling is derived. Moreover, since interruptible loads can positively participate as generators in the competitive electricity market, we consider these interruptible loads active control variables. Numerical example demonstrates efficiency of the proposed algorithm.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1993.10a
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• pp.118-118
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• 1993

We consider a discrete event dynamic system called periodic job shop, where an identical mixture of items called minimal part set(MPS) is repetitively produced in the same processing order and the primary performance measure is the cycle time. The precedence relationships among events(starts of operations) are represented by a directed graph with rocurront otructure. When each operation starts as soon as all its preceding operations complete(called earliest starting), the occurrences of events are modeled in a linear system using a special algebra called minimax algebra. By investigating the eigenvalues and the eigenvectors, we develop conditions on the directed graph for which a stable steady state or a finite eigenvector exists. We demonstrate that each finite eigenvector, characterized as a finite linear combination of a class of eigenvalue, is the minimum among all the feasible schedules and an identical schedule pattern repeats every MPS. We develop an efficient algorithm to find a schedule among such schedules that minimizes a secondary performance measure related to work-in-process inventory. As a by-product of the linear system approach, we also propose a way of characterizing stable steady states of a class of discrete event dynamic systems.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.835-840
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• 2009

Lately, Building Information Modeling (BIM) emerges as the most promising technology, now is expected to bring a great deal of improvement of productivity in every aspect of the construction industry. One of the BIM based scheduling is to use BIM model as a base for applying to schedule analysis and simulation tools. This type of tools may incorporate a various types of information such as the building model, construction method information, resource information, productivity information, rules and constraints to optimize activity sequencing. This paper proposes a framework of BIM based simulating system which can be used to optimize construction processes, especially for the floor construction cycle. For the purpose, all of the necessary components of the system will be defined and represented, and next an algorithm will be introduced to demonstrate the principle of simulating operation. The benefits of this technique are basically two : to test and optimize construction methods in respect of the construction duration and to reduce the floor construction cycle.