• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권9호
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• pp.3496-3514
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• 2015

One of the challenging tasks in Mobile Ad hoc Network is to discover precise optimal routing solution due to the infrastructure-less dynamic behavior of wireless mobile nodes. Ant Colony Optimization, a swarm Intelligence technique, inspired by the foraging behaviour of ants in colonies was used in the past research works to compute the optimal path. In this paper, we propose a Recurrent Ant Colony Optimization (RECACO) that executes the actual Ant Colony Optimization iteratively based on recurrent value in order to obtain an optimal path convergence. Each iteration involves three steps: Pheromone tracking, Pheromone renewal and Node selection based on the residual energy in the mobile nodes. The novelty of our approach is the inclusion of new pheromone updating strategy in both online step-by-step pheromone renewal mode and online delayed pheromone renewal mode with the use of newly proposed metric named ELD (Energy Load Delay) based on energy, Load balancing and end-to-end delay metrics to measure the performance. RECACO is implemented using network simulator NS2.34. The implementation results show that the proposed algorithm outperforms the existing algorithms like AODV, ACO, LBE-ARAMA in terms of Energy, Delay, Packet Delivery Ratio and Network life time.

• Journal of Chest Surgery
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• 제18권3호
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• pp.497-505
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• 1985

Bronchoplastic techniques represent the ideal surgical therapy for benign endobronchial tumors as well as tumors of low-grade malignant potential, such as bronchial adenomas, and for repair of traumatic airway injuries and benign strictures. This approach is also applicable to a select group of patients with carcinoma of the lung, with long-term survival being comparable to that achieved by standard pneumonectomy. Five bronchoplastic procedures were performed at Department of Thoracic and Cardiovascular Surgery, Seoul National University Hospital during 7 months periods from Dec. 1984 to Jun. 1985. Of the 5 patients, 3 patients were male and 2 patients were female and ages ranged from 8 years to 55 years old. The final diagnoses of 5 patients were as followed; traumatic bronchostenosis, endobronchial tuberculoma, carcinoid tumor, tuberculous bronchostenosis and traumatic bronchial fracture. Operative procedures of 5 patients were as followed; resection and end-to-end anastomosis of right main bronchus, left lower lobectomy and wedge resection of bronchus, left upper sleeve lobectomy, right middle and lower sleeve lobectomy and resection and end-to-end anastomosis of left main bronchus. And 2 lungs and 3 lobes could be preserved by these bronchoplastic procedures. There was no post-operative complication or mortality and all patients are being followed up without specific problem.

• Journal of Positioning, Navigation, and Timing
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• 제8권4호
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• pp.153-164
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• 2019

This paper presents the development of an end-to-end numerical simulator for signal design of the next generation global navigation satellite system (GNSS). The GNSS services are an essential element of modern human life, becoming a core part of national infra-structure. Several countries are developing or modernizing their own positioning and timing system as their demand, and South Korea is also planning to develop a Korean Positioning System (KPS) based on its own technology, with the aim of operation in 2034. The developed simulator consists of three main units such as a signal generator, a channel unit, and a receiver. The signal generator is constructed based on the actual navigation satellite payload model. For channels, a simple Gaussian channel and land mobile satellite (LMS) multipath channel environments are implemented. A software receiver approach based on a commercial GNSS receiver model is employed. Through the simulator proposed in this paper, it is possible to simulate the entire transceiver chain process from signal generation to receiver processing including channel effect. Finally, numerical simulation results for a simple example scenario is analyzed. The use of the numerical signal simulator in this paper will be ideally suited to design a new navigation signal for the upcoming KPS by reducing the research and development efforts, tremendously.

• 건축역사연구
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• 제14권2호
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• pp.21-40
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• 2005

The purpose of this study was to analyze the features of the avant-garde architecture in the end of the 20th Century based on the ontology as a metalanguage. In view of the results so for achieved, it is possible to say that the thought of becoming, topology, rhizome thought and the Deleuze's concepts of the fold and the event as ever-changing and evolving at any given time are found in the avant-garde architecture, and the introduction of ontological thought into architectural design encourage hopes for a more natural and existential quality in architecture. However, the avant-garde architecture in the end of the 20th century disclosed the limitation in the architectural expression of ontological thought due to the lack of fully understand on ontology. In conclusion, the ontological approach in architecture offers a new morphological methodology and a new way of programming considering the existential aspect of space through the bricoleur's means leaving the ontological meaning of architecture itself.

• 한국생산제조학회지
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• 제22권6호
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• pp.1003-1009
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• 2013

This paper presents a simple procedure to obtain the instantaneous cutting force constants needed to predict milling forces. Cutting force data measured in a series of slot milling tests were used to determine the cutting force constants at different feed rates. The values of the cutting force constants were determined directly at the tool rotation angle that maximized the uncut chip thickness. Then, the instantaneous cutting force constant was obtained as a function of the instantaneous uncut chip thickness. This approach can greatly enhance the accuracy of the mechanistic cutting force model for end milling. In addition, the influences of several cutting parameters on the cutting forces, such as the tool helix angle and axial depth of cut, were discussed.

• Computers and Concrete
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• 제26권5호
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• pp.397-409
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• 2020

The current study targets to estimate the contribution of the end-anchored FRP composites in resisting shear force using a soft computing tool i.e., adaptive neuro-fuzzy inference system (ANFIS). A total of 107 sets of data accumulated from literature was utilized for the development and evaluation of the current ANFIS model. A comparative analysis between the ANFIS predictions and the acquired experimental results has shown that the ANFIS predictions are in very good agreement with that of experimental ones. Additionally, the accuracy of the current ANFIS model has been weighed up against the estimates of nine widely adopted design guidelines. Based on various statistical parameters, it has been deduced that the effectiveness of the current ANFIS model is better than the considered design guidelines. Besides this, a parametric study was carried out to explore the combined effect of different parameters as well as the impact of individual parameters.

• 소음진동
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• 제9권2호
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• pp.285-294
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• 1999

Transient analysis for compressible fluid flow has been performed experimentally and analytically to study the dynamic characteristics of the end volume transmission lines following a sudden pressure change a its entrance. The numerical method was developed based on the method of characteristics. The sudden pressure at its entrance was generated by rupture of diaphragm in a shock tube. The sudden pressure was used to obtain the response, as input signal for the numerical analysis. The response to the sudden pressure at the end volume was measured using a pressure transducer. The experimental result shows good agreements with the numerical result. The effects of tube length, its diameter and end volume magnitude are evaluated on the responses of the pressure and on the damping factor. It is found that the viscous damping effects on the response through the transmission pipeline becomes larger with increasing pi;eline length and decreasing diameter of the pipe and the fluid-elastic stiffness decreases with increasing the terminal volume. The numerical approach presented in this paper can be very useful in designing the instrument and control system.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
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• pp.581-582
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• 2009

Continuous deep girders which transmit the gravity load from the upper wall to lower columns have frequently long end shear spans between the boundary of the upper wall and the face of the lower column. This paper presents the results of tests and analyses performed on three 1:2.5 scale specimens with long end shear spans, (the ratios of shear-span/height : 2.0

• Design & Manufacturing
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• 제17권4호
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• pp.24-32
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• 2023

In this study, we introduce research aimed at minimizing machining errors without compromising productivity by compensating for the machining errors caused by tool deformation. Our approach experimentally establishes the direct correlation between cutting depth and machining error, and creates predictive models using mathematical functions. This method allows for the prediction of compensated cutting depths to obtain the desired cutting profiles, thereby maximizing the compensation of machining errors in the cutting process.

• 한국정밀공학회지
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• 제16권6호
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• pp.83-89
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• 1999

This paper presents the in-process runout compensation methodology to improve the surface quality of circular contouring cut in end milling process. The runout compensation system is based on the manipulation of workpiece position relative to cutter in minimizing the cutting force oscillation at spindle frequency. the basic concept of this approach is realized on a end milling machine whose machining table accommodates a set of orthogonal translators perpendicular to the spindle axis. The system performed that measuring the runout related cutting force component, formulating PI controlling commands, and the manipulating the workpiece position to counteract the variation of chip load during the circular contouring cut. To evaluate the runout compensation system performance, experimental study based on the implementation of two-axes PI force control is presented in the context of cutting force regulation and part surface finish improvement.