• IE interfaces
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• v.14 no.4
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• pp.374-384
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• 2001

The objective of this paper is to design the dynamic route guidance system(DRGS) and develop a genetic algorithm(GA) for finding the multiple shortest paths in real traffic network. The proposed GA finds a collection of paths between source and destination considering turn-restrictions, U-turn, and P-turn that are genetically evolved until an acceptable solution is reached. This paper also shows the procedure to find the multiple shortest paths in traffic network of Seoul.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.11
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• pp.181-188
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• 2019

The migration path of a multiple-generation technology that occurs during a technological substitution by a new technology is important to understanding the phenomenon of technological substitution, and can contribute to understanding the process of technological innovation. This research defines the concept of migration path and develops a model of the types of migration paths by multiple dimensions (actor, generation, and time) in a multiple-generation technology. Based on a literature review and tracking of migration paths according to multiple dimensions, the definitions and types of migration paths were provided, and the accuracy of the model was verified based on a case study of the semiconductor industry. The migration paths of suppliers are modeled with three types (switching, leapfrogging, and new entrance paths), and the migration paths of customers are modeled with four types (switching, leapfrogging, new entrance, and diffusion paths) in a multiple-generation technology. This research will be useful for understanding the migration paths in the phenomenon of technological substitution, and can be applied to other industries in addition to the semiconductor industry, including various actors. In addition, suppliers and customers can understand technological substitution and can establish a technology strategy against their competitors.

• Journal of Korean Institute of Industrial Engineers
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• v.32 no.3
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• pp.226-235
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• 2006

Telematics is expected to be one of the fastest growing businesses in information technology area. It may create a new emerging market in industry related to automotive, telecommunications, and information services. Especially vehicle navigation service is considered as a killer application among telematics service applications. The current vehicle navigation service typically recommends a single path that is based on the traveling time or distance from the origin to the destination. The system provides two options for users to choose either via highway or via any road. Since the traffics and road conditions of big cities are very complicated and dynamic, the demand of multi-path guidance system is increasing in telematics market. The multi-path guidance system should allow drivers to choose a path based on their individual preferences such as traveling time, distance, or route familiarity. Using the Lawler's algorithm, it is possible to find multiple paths; however, due to the lengthy computational time, it is not suitable for the real-time services. This study suggests a computationally feasible and efficient heuristic multiple paths finding algorithm that is reliable for the real-time vehicle navigation services.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.4
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• pp.1406-1423
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• 2014

Multi-mode device which combines multiple access technologies into a device will offer more cost-effective solution than a sole access implementation. Its concurrent multipath transfer (CMT) technology can transmit media flows over multiple end-to-end paths simultaneously, which is essential to select at least two paths from all available paths. At real networks, different paths are likely to overlap each other and even share bottleneck, which can weaken the path diversity gained through CMT. Spurred by this observation, it is necessary to select multiple independent paths as much as possible to avoid underlying shared bottleneck between topologically joint paths. Recent research in this context has shown that different paths with shared bottleneck can weaken the path diversity gained through CMT. In our earlier work, a grouping-based multipath selection (GMS) mechanism is introduced and developed. However, how to estimating the selection is still to be resolved. In this paper, we firstly introduce a Selection Correctness Index (SCI) to evaluate the correctness of selection results in actual CMT experiment. Therefore, this metric is helpful to discuss and validate the accuracy of the output paths. From extensive experiments with a realized prototype, the proposed scheme provides better evaluation tool and criterion in various network conditions.

• Journal of Korean Society of Transportation
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• v.22 no.2 s.73
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• pp.121-130
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• 2004

In these days, multiple-path generation method is highly demanded in practice and research areas, which can represents realistically travelers behavior in choosing possible alternative paths. The multiple-path generation algorithm is one of the key components for policy analysis related to ATIS, DRGS and ATMS in ITS. This study suggested a method to generate multiple Possible paths from an origin to a destination. The approach of the suggested method is different from an other existing methods(K-shortest path algorithm) such as link elimination approach, link penalty approach and simulation approach. The result of the multi-label vine-building shortest path algorithm(MVA) by Kim (1998) and Kim(2001) was used to generate multiple reasonable possible paths with the concept of the rational upper boundary. Because the MVA algorithm records the cost, back-node and back-back node of the minimum path from the origin to the concerned node(intersection) for each direction to the node, many potential possible paths can be generated by tracing back. Among such large number of the potential possible paths, the algorithm distinguishes reasonable alternative paths from the unrealistic potential possible paths by using the concept of the rational upper boundary. The study also shows the very simple network examples to help the concept of the suggested path generation algorithm.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.8
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• pp.972-982
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• 1988

In multiprocessor systems, there are Omega network and M network among various MIN's which interconnect the processor and memory modules. Both one-path Omega network and two-path M network are composed of Log2N stages. In this paper, Augmented M network (AMN) with 2**k+1 paths and Augmented Omega network (AON) with 2**k paths are proposed. The proposed networks can be acomplished by adding K stage(s) to M network and Omega network. Using destination tag, routing algorithm for AMN and AON becomes simple and multiple faults are tolerant. By evaluating RST(request service time) performance of AMN and AON with (Log2N)+K stages, we demonstrated the fact that MMIN (AMN) with 2**k+1 paths performs better than MMIN(AON) with 2**k+1. paths.

• Journal of the military operations research society of Korea
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• v.17 no.2
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• pp.72-89
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• 1991

In transportation network problems, it is often desirable to select multiple number of the shortect paths. On problems of finding these paths, algorithms have been developed to choose single shortest path, k-shortest paths and k-shortest paths via p-specified nodes in a network. These problems consider the time as the main factor. In wartime, we must consider availability as well as time to determine the shortest transportation path, since we must take into account enemy's threat. Therefore, this paper addresses the problem of finding the shortest transportation path considering both time and availability. To accomplish the objective of this study, values of k-shortest paths are computed using the algorithm for finding the k-shortest paths. Then availabilties of those paths are computed through simulation considering factors such as rates of suffering attack, damage and repair rates of the paths. An optimal path is selected using any one of the four decision rules that combine the value and availability of a path.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.8
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• pp.3900-3916
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• 2019

The modern mobile devices are typically equipped with multiple network interfaces, e.g., 4G LTE, Wi-Fi, Bluetooth, but the current implementation of TCP can support only a single path at the same time. The Multipath TCP (MPTCP) leverages the multipath feature and provides (i) robust connection by utilizing another interface if the current connection is lost and (ii) higher throughput than single path TCP by simultaneously leveraging multiple network paths. However, if the performance between the multiple paths are significantly diverse, the receiver may have to wait for packets from the slower path, causing reordering and buffering problems. To solve this problem, previous MPTCP schedulers mainly focused on predicting the latency of the path beforehand. Recent studies, however, have shown that the path latency varies by a large margin over time, thus the MPTCP scheduler may wrongly predict the path latency, causing performance degradation. In this paper, we propose a new MPTCP scheduler called, choose fastest subflow (CFS) scheduler to solve this problem. Rather than predicting the path latency, CFS utilizes the characteristics of these paths to reduce the overall flow completion time by redundantly sending the last part of the flow to both paths. We compare the performance through real testbed experiments that implements CFS. The experimental results on both synthetic packet generation and actual Web page requests, show that CFS consistently outperforms the previous proposals in all cases.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.2B
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• pp.183-191
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• 2004

Single shortest path routing is known to perform poorly for Internet traffic engineering (TE) where the typical optimization objective is to minimize the maximum link load. Splitting traffic uniformly over equal cost multiple shortest paths in OSPF and IS-IS does not always minimize the maximum link load when multiple paths are not carefully selected for the global traffic demand matrix. However, among all the equal cost multiple shortest paths in the network, a set of TE-aware shortest paths, which reduces the maximum link load significantly, can be found and used by IP routers without any change of existing routing protocols and serious configuration overhead. While calculating TE-aware shortest paths. the destination-based forwarding constraint at a node should be satisfied, because an IP router will forward a packet to the next-hop toward the destination by looking up the destination prefix. In this paper, we present a problem formulation of finding a set of TE-aware shortest paths in ILP, and propose a simple heuristic for the problem. From the simulation results, it is shown that TE-aware shortest path routing performs better than default shortest path routing and ECMP in terms of the maximum link load with the marginal configuration overhead of changing the next-hops.

• ETRI Journal
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• v.44 no.6
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• pp.1004-1019
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• 2022

For autonomous driving without high-definition maps, we present a model capable of generating multiple plausible paths from egocentric images for autonomous vehicles. Our generative model comprises two neural networks: feature extraction network (FEN) and path generation network (PGN). The FEN extracts meaningful features from an egocentric image, whereas the PGN generates multiple paths from the features, given a driving intention and speed. To ensure that the paths generated are plausible and consistent with the intention, we introduce an attentive discriminator and train it with the PGN under a generative adversarial network framework. Furthermore, we devise an interaction model between the positions in the paths and the intentions hidden in the positions and design a novel PGN architecture that reflects the interaction model for improving the accuracy and diversity of the generated paths. Finally, we introduce ETRIDriving, a dataset for autonomous driving, in which the recorded sensor data are labeled with discrete high-level driving actions, and demonstrate the state-of-the-art performance of the proposed model on ETRIDriving in terms of accuracy and diversity.