• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.21 no.5
• /
• pp.78-89
• /
• 2022

Super - Bus Rapid Transit (S-BRT), adding the advantages of urban railroads to BRT, has emerged to solve the problem of low speed and reliability of the existing BRT. Notably, the S-BRT driveway is classified into exclusive lanes and roads, as BRT, in the domestic guidelines. However, S-BRT and BRT have different operating goals and characteristics, so it is necessary to systematize the S-BRT driveway. Therefore, this study classified an S-BRT driveway into exclusive lane, shared lane with overtaking lane, and shared lane without overtaking lane based on domestic conditions. Subsequently, a control strategy for transit signal priority in each driveway was presented by the study based on the characteristics of the driveway to achieve the S-BRT target service level. Finally, the S-BRT target service level was almost achieved, and the travel speed was high and increased in the order respectively in the exclusive lane, shared lane with overtaking lane, and shared lane without overtaking lane in the study. Hence, it is important to operate a transit signal priority considering the characteristics of each driveway when operating the S-BRT. In essence, this study is expected to be used as a reference for driveway design and transit signal priority operation when introducing S-BRT in each local government in the future.

• Journal of the Korean Society for information Management
• /
• v.39 no.3
• /
• pp.1-22
• /
• 2022

The purpose of this study is to propose a book recommendation system that can be used in school libraries. The book recommendation system applies an algorithm based on association rules using DLS lending data and is designed to provide personalized book recommendation services to school library users. For this purpose, association rules based on the Apriori algorithm and betweenness centrality analysis were applied and detailed functions such as descriptive statistics, generation of association rules, student-centered recommendation, and book-centered recommendation were materialized. Subsequently, opinions on the use of the book recommendation system were investigated through in-depth interviews with teacher librarians. As a result of the investigation, opinions on the necessity and difficulty of book recommendation, student responses, differences from existing recommendation methods, utilization methods, and improvements were confirmed and based on this, the following discussions were proposed. First, it is necessary to provide long-term lending data to understand the characteristics of each school. Second, it is necessary to discuss the data integration plan by region or school characteristics. Third, It is necessary to establish a book recommendation system provided by the Comprehensive Support System for Reading Education. Based on the contents proposed in this study, it is expected that various discussions will be made on the application of a personalization recommendation system that can be used in the school library in the future.

• Journal of the Korean GEO-environmental Society
• /
• v.24 no.9
• /
• pp.33-40
• /
• 2023

The lateral load which is applied to the pile foundation supporting the superstructure during an earthquake is divided into the inertia force of the upper structure and the kinematic force of the ground. The inertia force and the kinematic force could cause failure to the pile foundation through different complex mechanisms. So it is necessary to predict and evaluate interaction of the ground-pile-structure properly for the seismic design of the foundation. The interaction is affected by the lateral behavior of the structure, the length of the pile, the boundary conditions of the head, and the relative density of the ground. Confining pressure and ground stiffness change accordingly when the relative density changes, and it results that the coefficient of subgrade reaction varies depending on each system. Horizontal bearing behavior and capacity of the pile foundation vary depending on lateral load condition and relative density of the sandy soil. Therefore, the 1g shaking table tests were conducted to confirm the effect of the relative density of the dried sandy soil to dynamic behavior of the group pile supporting the superstructure. The result shows that, as the relative density increases, maximum acceleration of the superstructure and the pile cap increases and decreases respectively, and the slope of the p-y curve of the pile decreases.

• Proceedings of the Korean Society of Tobacco Science Conference
• /
• 1997.10a
• /
• pp.79-90
• /
• 1997

The world-wide cigarette market is becoming increasingly regulated. This involves restrictions on the freedom to advertise, restrictions on where people can smoke, and in some ways of most importance, limits on cigarette smoke deliveries. In particular, in an increasingly large number of countries maximum tar legislation is being enacted. In many cases, such as the European Union, this type of legislation is progressive and over time it is entirely conceivable that maximum permitted tar deliveries will be reduced to as low as 5 mg, possibly with additional restrictions on smoke nicotine deliveries. In addition, the pace of change is increasing as more and more countries embark on tar reduction programmes. The key challenge facing the cigarette industry is to manage these changes in such a way which ensures that product acceptability is maintained at as high a level as is possible in these circumstances. There are a number of ways of achieving this involving filter ventilation, modifying blends and using different filter constructions The real innovation comes when combining these in a way that gives the most acceptable balance of all these competing variables as far as the smoker is concerned. Undoubtedly, the nature of the filter is of crucial importance in designing the most acceptable low tar products, and this paper will discuss some of the filter types which are currently in use in the various low tar markets around the world. Also, some thoughts about the future in terms of new filter developments will be presented.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.33 no.2
• /
• pp.305-318
• /
• 2023

The complexity of software products led many manufacturers to stitch open-source software for composing a product. Using open-source help reduce the development cost, but the difference in the different development life cycles makes it difficult to keep the product up-to-date. For this reason, even the patches for known vulnerabilities are not adopted quickly enough, leaving the entire product under threat. Existing studies propose to use binary differentiation techniques to determine if a product is left vulnerable against a particular vulnerability. Despite their effectiveness in finding real-world vulnerabilities, they often fail to locate the evidence of a vulnerability if it is a small function that usually is inlined at compile time. This work presents our tool FunRank which is designed to identify the short functions. Our experiments using synthesized and real-world software products show that FunRank can identify the short, inlined functions that suggest that the program is left vulnerable to a particular vulnerability.

• Journal of Korean Elementary Science Education
• /
• v.42 no.1
• /
• pp.178-193
• /
• 2023

The aim of this study was to investigate differences in the achievement standards from the 2015 to the 2022 revised national science curriculum and to present the implications for science teaching under the revised curriculum. Achievement standards relevant to primary science education were therefore extracted from the national curriculum documents; conceptual domains in the two curricula were analyzed for differences; various kinds of centrality were computed; and the Louvain algorithm was used to identify clusters. These methods revealed that, in the revised compared with the preceding curriculum, the total number of nodes and links had increased, while the number of achievement standards had decreased by 10 percent. In the revised curriculum, keywords relevant to procedural skills and behavior received more emphasis and were connected to collaborative learning and digital literacy. Observation, survey, and explanation remained important, but varied in application across the fields of science. Clustering revealed that the number of categories in each field of science remained mostly unchanged in the revised compared with the previous curriculum, but that each category highlighted different skills or behaviors. Based on those findings, some implications for science instruction in the classroom are discussed.

• Journal of the Korean Geotechnical Society
• /
• v.26 no.8
• /
• pp.77-88
• /
• 2010

In this study, 1 g shaking table group pile tests were performed for various conditions of subgrade and pile spacing. The pile spacing was changed from three to seven times of pile diameters. It could be confirmed that the dynamic p-y curves for the group pile observed as the results of a series of shaking table tests show difference according to the pile spacing, the pile location within the pile group, the relative density of subgrade and the excess pore pressure during earthquake. The dynamic p-multipliers were calculated by comparing the dynamic p-y backbone curves of a single pile suggested by Yang (2009) and dynamic p-y curves for the group pile. Dynamic p-multiplier values overall increase as the relative density of subgrade and amplitude of input acceleration increase. The dynamic group pile effect was neglected, if the pile spacing was seven times as large as pile diameters. It was found that the exisiting p-multiplier values suggested by various researchers for the static and dynamic loading, and the values recommended by globally used specifications show difference with the test results by up to 0.7 (approximately 70%). Therefore, the dynamic p-multipliers were newly suggested according to the pile spacing and the relative density of subgrade using the test results.

• Journal of the Korean Geotechnical Society
• /
• v.25 no.12
• /
• pp.57-67
• /
• 2009

Along with the advanced construction technologies, the maximum size of coarse aggregate used for dam construction ranges from several cm to 1m. Testing the original gradation samples is not only expensive but also causes many technical difficulties. Generally, indoor tests are performed on the samples with the parallel grading method after which the results are applied to the design and interpretation of the actual geotechnical structure. In order to anticipate the exact behavior characteristics for the geotechnical structure, it is necessary to understand the changes in the shear behavior. In this study, the Large Triaxial Test was performed on the parallel grading method samples that were restructured with river bed sand-gravel, with a different maximum size, which is the material that was used to construct Dam B in Korea. And the Stress - Strain characteristics of the parallel grading method samples and the characteristics of the shear strength were compared and analyzed. In the test results, the coarse-grained showed strain softening and expansion behavior of the volume, which became more obvious as the maximum size increased. The internal angle of friction and the shear strength appeared to increase as the maximum size of the parallel grading method sample increased.

• Journal of the Korean Geotechnical Society
• /
• v.22 no.12
• /
• pp.67-76
• /
• 2006

The reasonable assessment of the shear stiffness of a dredged soft ground and soft clay is difficult due to the soil disturbance. This study addresses the development and application of a new in-situ shear wave measuring apparatus (field velocity probe: FVP), which overcomes several of the limitations of conventional methods. Design concerns of this new apparatus include the disturbance of soils, cross-talking between transducers, electromagnetic coupling between cables, self acoustic insulation, the constant travel distance of S-wave, the rotation of the transducer, directly transmitted wave through a frame from transducer to transducer, and protection of the transducer and the cable. These concerns are effectively eliminated by continuous improvements through performing field and laboratory tests. The shear wave velocity of the FVP is simply calculated, without any inversion process, by using the travel distance and the first arrival time. The developed FVP Is tested in soil up to 30m in depth. The experimental results show that the FVP can produce every detailed shear wave velocity profiles in sand and clay layers. In addition, the shear wave velocity at the tested site correlates well with the cone tip resistance. This study suggests that the FVP may be an effective technique for measuring the shear wave velocity in the field to assess dynamic soil properties in soft ground.

• Journal of the Korean Geotechnical Society
• /
• v.23 no.7
• /
• pp.5-16
• /
• 2007

The monitoring and investigation of underwater landslide help to understand its mechanism, increase the usefuless of design and construction and reduce the losses. This paper presents three high resolution geophysical techniques electrical resisitance, ultrasonic wave reflection imaging, and shear wave tomography conducted to determine the lab-scaled submerged landslide. Electrical resistance profiles of a soil mass obtained by an electrical resistance probe provide detailed information to assess the spatial distribution of the soil mass with milimetric resolution. An ultrasonic wave image obtained by recording the reflections from interfaces of different impedance materials permits detecting layers and landslide with submilimetric resolution. The pixel based image of immersed landslides is created by the inversion of the boundary information achieved from the traveling time of shear waves. The experimental results show that the ultrasonic wave imaging and the electrical resistance can provide complementary information; and their association with S-wave tomography image can produce a 3-D view of the underwater landslide. This study suggests that geophysical techniques may be effective tools for the detection of the underwater landslides and spatial distribution offshore.