• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.36 no.6B
• /
• pp.583-591
• /
• 2011

We presents the architecture of the 2.5 Gbps hybrid PON link which can increase of the transmission distance and link capability, and split ratio by using a colorless DWDM-PON and O/E/O based reach extender into an existing G-PON link. A RSOA based DWDM-PON to apply the feeder fiber can provide a link capacity of 32 larger that of a legacy G-PON. The reach extender converts the wavelength of DWDM-PON to G-PON through GTC frame regeneration at the remote node, and can provide a burst reset signal in order to extract upstream burst signal, simultaneously. The proposed hybrid PON enable a legacy G-PON to operate over the maximum 60 km distance with a 128-way split per WDM wavelength.

• The KIPS Transactions:PartA
• /
• v.17A no.2
• /
• pp.103-112
• /
• 2010

Cluster sensor network is a sensor network where input nodes crowd densely around some nuclei. Steiner minimum tree is a tree connecting all input nodes with introducing some additional nodes called Steiner points. This paper proposes a mechanism for efficient construction of a cluster sensor network connecting all sensor nodes and base stations using connections between nodes in each belonged cluster and between every cluster, and using repetitive constructions of approximate Steiner minimum trees. In experiments, while taking 1170.5% percentages more time to build cluster sensor network than the method of Euclidian minimum spanning tree, the proposed mechanism whose time complexity is O($N^2$) could spend only 20.3 percentages more time for building 0.1% added length network in comparison with the method of Euclidian minimum spanning tree. The mechanism could curtail the built trees' average length by maximum 3.7 percentages and by average 1.9 percentages, compared with the average length of trees built by Euclidian minimum spanning tree method.

• Journal of the Korean association of regional geographers
• /
• v.15 no.5
• /
• pp.590-603
• /
• 2009

This report studies what connections was between Ethnic education movement in Bukkando and natural and human knowledge environment as a way to complement total absence of studying Anti-Japanese Movement at the Geographic levels. The summary is as following: At first, the Korean villages, where almost all spread the national schools, so there was a very close relationship. Both from a Longjing as the central plain area to the proliferation of surrounding areas. Second, schools that was adjacent to trunk road were given a great deal of weight on the connection with traffic. After that, however, it decreased gradually. Third, the national schools suffered the dual intervention from China and Japan, experienced a difficult development process. the schools which built by Japan were spreaded areas where concentrate the schools which built by Japan were spreaded areas where concentrated many national schools, both have a close relationship. before 3.13 movement, the distribution of schools that established by the Chinese mainly spreaded the areas concentrated national schools. But, after the 3.13 movement, it appeared a tendency to spread to the Korean people area where relatively dwelled a few people.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.9
• /
• pp.6214-6220
• /
• 2015

A track circuit has used stably more than 100 years for detecting train position, but solution of track circuit sort circuit incapacity due to a rust is necessary for side line in station yard, coast line and level crossing for conventional line in rural line. Domestically, Axle Counter System(ACS) has partially used for Hot Box System for high speed line and turnout for CBTC system. In contrast, most of countries has used ACS not only trunk line but also rural line and its application has increased for metro, electric car and industrial railway. In this paper, we has verified the operating status of ACS which installed with existing track circuit through log analsis to implement pilot application in mail track and turnout in station yard. And interface test with interlocking system has conducted at Obong shunting yard, as well as Cheongju station and has analyzed test result. Based on a test result, we made fail safe design, manufacturing skill and established system requirement specification for the smooth operation and maintenance.

• Journal of KIISE
• /
• v.42 no.1
• /
• pp.44-53
• /
• 2015

Control flow information is useful in the analysis and comparison of programs. Virtualization-obfuscation hides control structures of the original program by transforming machine instructions into bytecode. Direct examination of the resulting binary reveals only the structure of the interpreter. Recovery of the original instructions requires knowledge of the virtual machine architecture, which is randomly generated and hidden. In this paper, we propose a method to reconstruct original control flow using only traces generated from the obfuscated binary. We consider traces as strings and find an automaton that represents the strings. State transitions in the automaton correspond to the control transfers in the original program. We have shown the effectiveness of our method with commercial obfuscators.

• Smart Media Journal
• /
• v.6 no.1
• /
• pp.22-29
• /
• 2017

Due to the rapid advancement and distribution of smart devices of late, document data on the Internet is on the sharp increase. The increment of information on the Web including a massive amount of documents makes it increasingly difficult for users to understand corresponding data. In order to efficiently summarize documents in the field of automated summary programs, various researches are under way. This study uses TextRank algorithm to efficiently summarize documents. TextRank algorithm expresses sentences or keywords in the form of a graph and understands the importance of sentences by using its vertices and edges to understand semantic relations between vocabulary and sentence. It extracts high-ranking keywords and based on keywords, it extracts important sentences. To extract important sentences, the algorithm first groups vocabulary. Grouping vocabulary is done using a scale of specific weight. The program sorts out sentences with higher scores on the weight scale, and based on selected sentences, it extracts important sentences to summarize the document. This study proved that this process confirmed an improved performance than summary methods shown in previous researches and that the algorithm can more efficiently summarize documents.

• Journal of Korean Society of Transportation
• /
• v.19 no.1
• /
• pp.115-129
• /
• 2001

The purpose of this study is to develop a cycle-free signal timing model for minimizing delays based on Third-generation control concept using Genetic Algorithm. A special feature of this model is its ability to manage delays of turning movements on the cycle basis. The model produces a cycle-free based signal timing(cycles and green times) for each intersection to minimize delays of turning movements on the cycle basis. The performance of cycle-free signal timings was evaluated on normal (v/c = 0.7) and oversaturated (v/c=1.0) conditions. The performance measures are throughput and the number of queued vehicles at the end of green time. The result shows that the cycle free signal timing is superior to the fixed signal timing to manage traffic flows of intersections; (1) the proposed model accomplishes the basic objective of the research, producing cycle free signal timings on the cycle basis, (2) on normal conditions, cycle free signal timings produce less queued vehicles at the end of green time, and (3) on oversaturated conditions, the cycle free signal timing is superior to the fixed signal timing to manage saturated traffic flows of intersections.

• Journal of Korean Society of Transportation
• /
• v.26 no.4
• /
• pp.7-16
• /
• 2008

Severe congestion is happening at urban freeway off-ramps in Seoul. Major causes of congestion at off-ramps are a shortage of capacity and inefficient signal operations at the downstream intersection at off-ramps. It is necessary to control congestion by improving design or operations in the downstream intersection. In this study, the authors analyzed the case of the Jungdong interchange that was improved for design in the downstream intersection. When a freeway and an arterial road cross, diamond interchanges are usually selected with a single-point urban interchange (SPUI) as an alternative. To compare the effectiveness of a diamond interchange with a SPUI, the authors applied these two configurations to the Jungdong interchange using a simulation. The result of the analysis shows that congestion at off-ramps in diamond interchanges can be reduced by improving signal operations such as the application of "4 phase with overlaps" and that diamond interchanges are more efficient than a SPUI with a frontage road. Efficient operation of the downstream intersection by these findings can minimize congestion of not only the downstream intersection but also the freeway mainline.

• Journal of Korean Society of Transportation
• /
• v.28 no.5
• /
• pp.77-87
• /
• 2010

In the last five years, Korea has supplied many more bicycle facilities than in the last several decades combined. However, have bicyclists increased in proportion to investment? If bicyclists are avoiding existing bicycle related facilities, including off-road bicycle facilities, it could be because suppliers did not consider bicyclists' preferences in their planning process. In this paper, the authors tried to understand the bicyclists' behavioral and route choice characteristics using stated preference surveys and a logit model, using commuting time in Daejeon Metropolitan City, Korea. The results show that nine factors affect the route choice behavior of bicyclists. In particular, bicyclists preferred sub-arterial roads to off-road, dedicated bicycle facilities in residential area. It means that bicyclists like a seamless bicycle route and that a buffer zone between car lanes and bicycle lanes or 50 km/h speed limits for cars are necessary for bicycle lanes that are not physical separated.

• Journal of Korean Society of Water and Wastewater
• /
• v.13 no.3
• /
• pp.73-82
• /
• 1999

In this study, the optimal analysis for pipe network is performed for the combined ideal pipe network system(CASE 1, CASE 2 and CASE 3) which is composed of 25 nodes, 41 elements, and 1 fixed nodal head with evaluating pressure variation distribution of main and branch in grid composed drainage pipe network. The linear analysis technique used as the analysis method in this study, the KYPIPE being used extensively as the linear technique to design and analysis of pipe network is applied. Firstly, in the analysis of pipe network, the CASE 2 and CASE 3 supply same thing(value) in the result of considering the total flow provided each pipeline, but in the general intension in the case of CASE 2, relative width of supply is more large than CASE 1 and CASE 3. Secondly, in the analysis technique of pipe network, CASE 3 is analysed largest as a result of comparing with same heads, and in the order of their size CASE 2 and CASE 1 were determined but the difference doesn't appear to be obvious. Thirdly, as the result of determining main factor, pressure in the design and analysis of net work. CASE 3 is from Node 3 to 25 than CASE 1 and CASE 2 and it is determined in the order of their size, CASE 2 and CASE 1. Finally, in this study, discharge flow distribution is evaluated in the same condition with 3-type CASE in the case of branch position for designing optimal composed drainage pipe network. As the result of that, branch pipe perform. Therefore, it is thought that the efficient and reasonable management of water supply and sewerage design will be possible if it give all our energies to study at the pipe system design in and out of country in the future.