• Smart Structures and Systems
• /
• 제5권2호
• /
• pp.193-207
• /
• 2009

A framework for structural health monitoring (SHM) systems is presented utilizing a recent 3.5 generation mobile telecommunication technology, HSDPA (High Speed Downlink Packet Access). It may be effectively applied to monitoring bridges, cut-slopes, and other facilities located in rural areas where the conventional Internet service is not readily available, since HSDPA is currently commercialized in 86 countries to make the Internet access possible in anywhere the mobile phone service is available. The proposed SHM framework is also incorporating remote desktop software to have remote control/operation of the SHM systems. The feasibility of the proposed framework has been demonstrated by field tests on a highway bridge in operation. One can expect that fast advances in the mobile telecommunication technology will further enhance the performance of the SHM network using the proposed framework for bridges and other facilities located in remote areas without the conventional wired Internet service.

• 상하수도학회지
• /
• 제14권4호
• /
• pp.311-317
• /
• 2000

The operation of flocculation process and the evaluation thereof have been mainly based on G, t and $G{\times}t$ values which are available from design guidelines and texts. However, their suggested ranges are too wide to find the optimum condition specific to a particular water treatment plant and none of the existing method can be used to evaluate and suggest the optimum operational condition. Recently, a commercially available particle counter is found to be useful in determining the flocculation process based on the particle dynamics. The optimum condition is defined as one that best suits the purpose of flocculation; the number of small particles should decrease, while that of large particles should increase. The experiments were performed at two conventional water treatment plants in Korea, one with horizontal mechanical flocculators, and another with vertical type mechanical flocculators. In this paper, experiences to evaluate the flocculation process and to suggest the optimum operation condition will be presented. Although particle counting method is found to be beneficial compared to any other existing methods, the optimum condition is very much site-specific and should be evaluated at each water treatment plant for different conditions.

• 산업경영시스템학회지
• /
• 제43권4호
• /
• pp.217-228
• /
• 2020

The ROK Army must detect the enemy's location and the type of artillery weapon to respond effectively at wartime. This paper proposes a radar positioning model by applying a scenario-based robust optimization method i.e., binary integer programming. The model consists of the different types of radar, its available quantity and specification. Input data is a combination of target, weapon types and enemy position in enemy's attack scenarios. In this scenario, as the components increase by one unit, the total number increases exponentially, making it difficult to use all scenarios. Therefore, we use partial scenarios to see if they produce results similar to those of the total scenario, and then apply them to case studies. The goal of this model is to deploy an artillery locating radar that maximizes the detection probability at a given candidate site, based on the probability of all possible attack scenarios at an expected enemy artillery position. The results of various experiments including real case study show the appropriateness and practicality of our proposed model. In addition, the validity of the model is reviewed by comparing the case study results with the detection rate of the currently available radar deployment positions of Corps. We are looking forward to enhance Korea Artillery force combat capability through our research.

• 한국토양비료학회지
• /
• 제32권3호
• /
• pp.268-273
• /
• 1999

토지이용 유형과 유효인산 함량이 다양한 56개 토양을 대상으로 범용 분광광도계를 사용한 Lancaster법과 분석과정 및 측정과정을 간편화시킨 Soiltek$^{(R)}$ KA-1에서 제시하는 방법으로 측정한 유효인산함량에 대하여 정확도 및 정밀도를 비교 분석하였다. 두 방법으로 분석된 인산함량은 고도의 유의성 있는 정의상관 ($r=0.998^{***}$)을 보였으며, 기울기는 0.97로 거의 일치하여 두 방법간의 정확성은 차이가 없었다. 또한, 두 방법으로 측정된 인산함량 분석결과의 표준편차, CV, 상대정밀도(RS)는 거의 차이가 없으므로 정밀도에서도 차이가 없었다. 따라서, 분석과정 및 기기조작의 편리성 및 신속성을 고려한다면 Soiltek$^{(R)}$ KA-1에서 제시하는 방법으로 유효인산 함량을 측정하는 것도 유용한 방법이라고 생각된다.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2007년도 춘계학술대회B
• /
• pp.2775-2780
• /
• 2007

The ballistic range has long been employed in a variety of engineering fields such as high-speed impact engineering, projectile aerodynamics and aeroballistics, since it can create very high-pressure states in a short time. Since the operation of the ballistic range includes many complicated processes, each should be studied in detail for the best operation of the device. One of the main processes which have a major influence in its operation is the compression of the driver gas. Most of the studies available in this field hardly discuss this process in detail and thus lack a proper understanding of its effect. In the present study, a computational analysis has been made to investigate the compression process in the pump tube of a ballistic range. The results obtained are validated with some experimental data. It is seen that the pump tube parameters and the piston mass significantly affect the compression process and the time to build up the required diaphragm rupture pressure.

• 전기학회논문지
• /
• 제58권7호
• /
• pp.1287-1293
• /
• 2009

This paper presents an application of Harmony Search (HM) meta-heuristic optimization algorithm for optimal operation of microgrid system. The microgrid system considered in this paper consists of a wind turbine, a diesel generator, and a fuel cell. An one day load profile which divided 20 minute data and wind resource for wind turbine generator were used for the study. In optimization, the HS algorithm is used for solving the problem of microgrid system operation which a various generation resources are available to meet the customer load demand with minimum operating cost. The application of HS algorithm to optimal operation of microgrid proves its effectiveness to determine optimally the generating resources without any differences of load mismatch and having its nature of fast convergency time as compared to other optimization method.

• Industrial Engineering and Management Systems
• /
• 제15권2호
• /
• pp.131-142
• /
• 2016

We consider a multi-server queueing system without buffer and with two types of customers as a model of operation of a mobile network cell. Customers arrive at the system in the marked Markovian arrival flow. The service times of customers are exponentially distributed with parameters depending on the type of customer. A part of the available servers is reserved exclusively for service of first type customers. Customers who do not receive service upon arrival, can make repeated attempts. The system operation is influenced by random factors, leading to a change of the system parameters, including the total number of servers and the number of reserved servers. The behavior of the system is described by the multi-dimensional Markov chain. The generator of this Markov chain is constructed and the ergodicity condition is derived. Formulas for computation of the main performance measures of the system based on the stationary distribution of the Markov chain are derived. Numerical examples are presented.

• 한국농공학회논문집
• /
• 제48권2호
• /
• pp.27-35
• /
• 2006

Large dams are managed with operation standard and flood forecasting systems, while small dams do not have management method generally. Shortage of water resources and natural disasters due to drought and flood raised public concerns for management of small dams. Most of small dams are irrigation dams, which need diversified water uses. However, the lack of systematic management of small dams have caused serious water wastage and increased natural disasters. Storage management method and system were developed to solve these problems in small dams. The system was applied to Seongju dam for effective management. The storage management method was established considering hydrology simulation and statistical analysis using the system. This method can bring additional available water, even in the same conditions of the water demand and the supply conditions of watershed. It can improve the flood control capacity and water utilization efficiency by' the flexible operation of storage space.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1999년도 하계학술대회 논문집 C
• /
• pp.1262-1266
• /
• 1999

More precise operation and control is required to ensure the stability and security of modern large power systems that is a complicated and widely dispersed structure. To ensure the precise operation and control of modern power system, most of all, precise monitoring and measurement of the various state values of power system is required. This paper discusses phasor measurement unit using synchronization signals from the GPS satellite system- Synchronized Phasor Measurement Unit. Considering the power system operation state, the transmitting data format over modems is defined. To provide all available information, PMU process the measurements to generate three phase symmetrical component. This paper proposes the transmitted data format and implements the PMU model using EMTP/Models. The validity of proposed model is confirmed through several contingency on the simple power system.

• 산업경영시스템학회지
• /
• 제35권2호
• /
• pp.37-44
• /
• 2012

This paper focuses on scheduling problems arising in the military. In planned artillery attack operations, a large number of threatening enemy targets should be destroyed to minimize fatal loss to the friendly forces. We consider a situation in which the number of available weapons is smaller than the number of targets. Therefore it is required to develop a new sequencing algorithm for the unplanned artillery attack operation. The objective is to minimize the total loss to the friendly forces from the targets, which is expressed as a function of the fire power potential, after artillery attack operations are finished. We develop an algorithm considering the fire power potential and the time required to destroy the targets. The algorithms suggested in this paper can be used in real artillery attack operations if they are modified slightly to cope with the practical situations.