• Economic and Environmental Geology
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• v.6 no.4
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• pp.201-216
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• 1973

Being believed thus far to be distributed in the wide areas in the vicinity of Seoul, the capital city of Korea, the Yonchon System in its type locality in Yonchon-gun from which the name derived was never previously traced down or correlated to the Precambrian metamorphic complex in Seoul area where the present study was carried out. Due to in accessibility to Yonchon area, the writer also could not trace the system down to the area studied so as to correlate them. The present study endeavored to differentiate general stratigraphy and interprete the structure of the metamorphic complex in the area. In spite of the complexity of structure and rapid changes in lithofacies of the complex, it was succeeded to find out the key bed by which the stratigraphy and structure of the area could be straightened out. The keybeds were the Buchon limestone bed in the western parts of the area; Daisongri quartzite bed cropped out in the southeastern area; Jangrak quartzite bed scattered in the several localities in the northwest, southwest, and eastern parts of the area; and Earn quartzite bed isolated in the eastern part of the area. These keybeds together with the broad regional structure made it possible to differentiated the Precambrian rocks in ascending order into the Kyonggi metamorphic complex, Jangrak group and Chunsung group which are in clinounconformable relation, and the first complex were again separated in ascending order into Buchon, Sihung, and Yangpyong metermorphic groups. Althcugh it has being vaguely called as the Yonchon system thus far, the Kyonggi metamorphic complex have never been studied before. The complex might, however, belong to early to early-middle Precambrian age. The Jangrak and Chunsung group were correlated to the Sangwon system in North Korea by the writer (1972), but it became apparent that the rocks of the groups have different lithology and highly metamorphosd than those of the Sangwon system which has thick sequence of limestone and slightly metamorphosed. Being deposited in the margin of the basin, it is natural that the groups poccess terrestrial sediments rather than limestone, yet no explanation is at hand as to what was the cause of bringing such difference in grade of metamorphism. Thus the writer attempted to correlate the both groups to those of pre-Sangwon and post-Yonchon which might be middle to early-late Precambrian time. Judging from difference in grade of deformation and unconformity between the Kyonggi metamorphic complex, Jangrak group, and Chunsung group, three stages of orogeny were established: the Kyonggi, Jangrak orogenies, and Chunsung disturbance toward younger age. It is rather astonishing to point out that the structure of these Precambrian formations. was not effected by Daebo orogeny of Jurassic age. The post-tectonic block faulting was accompanied by these orogenies, and in consequence NNE and N-S trending faults were originated. These faulting were intermittented and repeated until Daebo orogeny at which granites intruded along these faults. The manifestation of alignment of these faults is indicated by the parallel and straight linear development of valleys and streams in the Kyonggi Massifland.

• Journal of the Korean Society for Nondestructive Testing
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• v.36 no.5
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• pp.370-376
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• 2016

Corrosion on the surface of a structure can generate cracks or cause walls to thin. This can lead to fracturing, which can eventually lead to fatalities and property loss. In an effort to prevent this, laser imaging technology has been used over the last ten years to detect thin-plate structure, or relatively thin piping. The most common laser imaging was used to develop a new technology for inspecting and imaging a desired area in order to scan various structures for thin-plate structure and thin piping. However, this method builds images by measuring waves reflected from defects, and subsequently has a considerable time delay of a few milliseconds at each scanning point. In addition, the complexity of the system is high, due to additional required components, such as laser-focusing parts. This paper proposes a laser imaging method with an increased scanning speed, based on excitation and the measurement of standing waves in structures. The wavenumber of standing waves changes at sections with a geometrical discontinuity, such as thickness. Therefore, it is possible to detect defects in a structure by generating standing waves with a single frequency and scanning the waves at each point by with the laser scanning system. The proposed technique is demonstrated on a wall-thinned plate with a linear thickness variation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.99-110
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• 2017

Improving tracking performance by estimating the status of multiple targets using radar is important. In a clutter environment, a joint event occurs between the track and measurement in multiple target tracking using a tracking filter. As the number increases, the joint event increases exponentially. The problem to be considered when multiple target tracking filter design in such environments is that first, the tracking filter minimizes the rate of false track alarmsby eliminating the false track and quickly confirming the target track. The purpose is to increase the FTD performance. The second consideration is to improve the track maintenance performance by allocating each measurement to a track efficiently when an event occurs. Through two considerations, a single target tracking data association technique is extended to a multiple target tracking filter, and representative algorithms are JIPDAF and LM-IPDAF. In this study, a probabilistic evaluation of many hypotheses in the assignment of measurements was not performed, so that the computation amount does not increase nonlinearly according to the number of measurements and tracks, and the track existence probability based on the track density The LM-IPDAF algorithm was introduced. This paper also proposes a method to reduce the computational complexity by improving the clutter density estimation method for calculating the track existence probability of LM-IPDAF. The performance was verified by a comparison with the existing algorithm through simulation. As a result, it was possible to reduce the simulation processing time by approximately 20% while achieving equivalent performance on the position RMSE and Confirmed True Track.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.5
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• pp.232-242
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• 2002

In a MPLS(Multiprotocol Label Switching) network, it is important to reduce the number of labels and LSP(Lable Switched Path)s for network resource management. MTP(Multipoint-to-Point) LSP can be used to solve this problem. In consideration of traffic engineering, MTP LSP must be chosen to enhance the availability of network and link utilization. Also, a fast mechanism to setup MTP LSPs is required for rerouting capability against link failure. In this paper, we propose a fast MTP LSP traffic engineering of multipath MTP LSP by using a mapping of a MTP LSP upon Diffserv PHBs(Per Hop Behavior) in a Diffserv-capable MPLS network. In the proposed traffic engineering, we determine multiple MTP LSPs in a hierarchical manner according to the characteristics of different services. By using Monte-Carlo method for traffic load balancing process, it provides fast rerouting capability in case of frequent link failure across large network. Out method produces to be nearly optimal within reasonable run-times. It's time complexity is in O( Cn$^2$logn) as conventional multipath routing and it is much faster than Linear Programming approach. Simulation results show that the proposed traffic engineering can be controlled effectively in an administrative manner and enhance the availability of network in comparison with conventional multipath routing.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.5
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• pp.263-269
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• 2014

In this paper, I disprove Hadwiger conjecture of the vertex coloring problem, which asserts that "All $K_k$-minor free graphs can be colored with k-1 number of colors, i.e., ${\chi}(G)=k$ given $K_k$-minor." Pursuant to Hadwiger conjecture, one shall obtain an NP-complete k-minor to determine ${\chi}(G)=k$, and solve another NP-complete vertex coloring problem as a means to color vertices. In order to disprove Hadwiger conjecture in this paper, I propose an algorithm of linear time complexity O(V) that yields the exact solution to the vertex coloring problem. The proposed algorithm assigns vertex with the minimum degree to the Maximum Independent Set (MIS) and repeats this process on a simplified graph derived by deleting adjacent edges to the MIS vertex so as to finally obtain an MIS with a single color. Next, it repeats the process on a simplified graph derived by deleting edges of the MIS vertex to obtain an MIS whose number of vertex color corresponds to ${\chi}(G)=k$. Also presented in this paper using the proposed algorithm is an additional algorithm that searches solution of ${\chi}^{{\prime}{\prime}}(G)$, the total chromatic number, which also remains NP-complete. When applied to a $K_4$-minor graph, the proposed algorithm has obtained ${\chi}(G)=3$ instead of ${\chi}(G)=4$, proving that the Hadwiger conjecture is not universally applicable to all the graphs. The proposed algorithm, however, is a simple algorithm that directly obtains an independent set minor of ${\chi}(G)=k$ to assign an equal color to the vertices of each independent set without having to determine minors in the first place.

• Journal of Life Science
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• v.28 no.5
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• pp.587-596
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• 2018

This study aims to observe changes in heart-rate variability (HRV) indices induced by e-cigarette and conventional-cigarette smoking and to compare the differences in acute cardiac autonomic regulation. All participants (n=41) were exposed to both e-cigarette smoke (ES) and conventional cigarette smoke (CS) in a randomized crossover trial. HRV analysis was performed during each smoking session based on a recorded r-r interval 10 minutes before smoking and at specified recovery periods (REC1, 0-5 min; REC2, 5-10 min; REC3, 10-15 min; REC4, 15-20 min; REC5, 20-25 min; and REC6, 25-30 min). ES led to a significantly increased cardiac sympathetic index (LF/HF ratio) compared with the baseline, and it shifted the sympathovagal balance toward sympathetic predominance, including reduction in the complexity of the interbeat interval (SampEn). In REC1 after ES, only decreases of parasympathetic indices such as rMSSD, pNN50, HF, and SD1 were indicated. CS sessions produced not only an increased LF/HF ratio during smoking and recovery periods (REC1 and REC4) but also enhanced sympathetic predominance on autonomic balance during smoking and recovery periods (REC1, REC2, and REC4). In the CS trials, parasympathetic indices of time and non-linear analysis (rMSSD, pNN50, and SD1) were decreased during smoking and in REC1 to REC5. SampEn was also reduced during smoking and REC1 to REC4. Acute sympathoexcitatory effects induced by e-cigarette use produced statistically significant results. Parasympathetic withdrawal after smoking suggests that e-cigarettes may cause increased cardiovascular risk.

• Journal of the Korea Society of Computer and Information
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• v.18 no.5
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• pp.113-120
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• 2013

This paper proposes an algorithm that proves an NP-complete 4-color theorem by employing a linear time complexity where $O(n)$. The proposed algorithm accurately halves the vertex set V of the graph $G=(V_1,E_1)$ into the Maximum Independent Set (MIS) $\bar{C_1}$ and the Minimum Vertex Cover Set $C_1$. It then assigns the first color to $\bar{C_1}$ and the second to $\bar{C_2}$, which, along with $C_2$, is halved from the connected graph $G=(V_2,E_2)$, a reduced set of the remaining vertices. Subsequently, the third color is assigned to $\bar{C_3}$, which, along with $C_3$, is halved from the connected graph $G=(V_3,E_3)$, a further reduced set of the remaining vertices. Lastly, denoting $C_3$ as $\bar{C_4}$, the algorithm assigns the forth color to $\bar{C_4}$. The algorithm has successfully obtained the chromatic number ${\chi}(G)=4$ with 100% probability, when applied to two actual map and two planar graphs. The proposed "four color algorithm", therefore, could be employed as a general algorithm to determine four-color for planar graphs.