• International Journal of Highway Engineering
• /
• v.5 no.2 s.16
• /
• pp.15-24
• /
• 2003

The performance of waterproofing system (WPS) is known to be a function of many complex interaction of material factors, design details, and the quality of construction, but it is mainly determined by the bond strength, which is measured by tensile adhesive strength (TAS) test. to the concrete bridge deck. In this research, eight waterproofing membranes were selected from commercial market and the tensile adhesive characteristics of the WPS on concrete bridge deck were investigated in view of various factor in asphalt pavement. The factors include type of asphalt mixture, pavement thickness, paving temperature and influence of wheel loading. TAS test of different asphalt pavement types showed that TAS of WPS under SMA (Stone Mastic Asphalt) pavement was greater than that under dense asphalt pavement. TAS of sheet membranes was improved as the compaction temperature of asphalt concrete increase, but TAS of liquid membranes were not. The influence of thickness of pavement val minimal with given laboratory test condition. TAS of sheet membranes after wheel tracking test were in the order of the sites under wheel path (UWP), before wheel tracking (BWT) and nearby wheel path (NWP). Since TAS of the same WPS of UWP was higher than TAS of BWT, wheel loading had function of pressing WPS resulting in higher adhesive strength. But liquid membranes were variable on types. The feature of detached interface after TAS test showed that sheet types were all detached in between deck concrete and WPS, and liquid types were detached in between asphalt pavement and WPS.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.29 no.6
• /
• pp.677-685
• /
• 2011

In order to enhance public transportation and to maintain information credibility, improvement of accuracy regarding route and positional information of public transport is very significant. There have been a variety of methods using GPS to measure accuracy of location-based services. However, the researches of evaluation regarding kinematic position of linear objects measured by vehicle/kinematic GPS are still insufficient. That's why our paper aims to suggest method of evaluation accuracy on a real-time bus route surveyed by GPS by SBM(Single Buffering Method). To make it come true, we compared the findings on the static and dynamic positioning by using PP(Point Positioning), DGPS and GPS/INS integrated systems and analyzed the accuracy and error effects among them, focusing on Anyang city. Consequently, we can find out that in case of P.P. comparing positioning accuracy between RTK DGPS and GPS/INS, both of them have survey result within a margin of error of 5m. More importantly, we can evaluate positional accuracy of each GPS system based on the work provision of a public survey such as error for P.P.(14.5m, 18.1m), DGPS(16.9m, 18.5m), and GPS/INS(18.4m, 18.5m). We are expecting that proposed method in our paper can be utilized in a wide range of categories such as feasibility testing of GPS field survey and high accuracy of positioning for Bus Information System.

• Membrane Journal
• /
• v.23 no.2
• /
• pp.112-118
• /
• 2013

Polyancrylonitrile nanofiber membrane (PAM) was prepared by using the electrospinning method with a solution of polyacrylonitrile (PAN) in DMF. The pore-diameter of PAMs and the number of PAM's layer were controlled for the microfiltration (MF) application. In addition, in order to improve the water-flux, AN-PEGMA copolymers have been synthesized via free radical polymerization with poly (ethylene glycol) methyl ether methacrylate and azobisisobutylronitrile (AIBN), and then PAN/AN-PEGMA nanofiber membranes (PAM/APM) were prepared by electrospinning with a mixture of PAN (9 wt%) and AN-PEGMA (3 wt%) in DMF (88 wt%). The prepared membranes were investigated with FT-IR and E.D.S. It was confirmed through scanning electron microscope (SEM), porometer, and porosity analysis that the porous membrane with a uniform diameter (400~600 nm) and a uniform pore characteristics (0.5~0.4 ${\mu}m$) was prepared. For the MF application, water-flux measurements were investigated and then the result was shown that the water permeability value of PAM/APMs introduced AN-PEGMA copolymers was relatively higher than that of the PVdF commercial membrane. From these results, PAN nanofiber membranes prepared by electrospinning could be utilized as a MF membrane.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.29 no.4
• /
• pp.550-561
• /
• 2019

Objectives: The purpose of this study is to provide basic data for the improvement of the working environment for health prevention and related countermeasures for shift workers. This study was conducted based on the Fifth Korean Working Conditions Survey (KWCS), which analyzed the health effects of shift work forces and compared them with preceding studies. Methods: By analyzing secondary rates using raw data from the 5th KWCS, 4,870 (9.7%) of the 50,184 total study subjects were divided into shift work and 45,314 (90.3%) non-shift work groups based on the response to shift status. Variables that could affect work health issues were identified and corrected. A cross-analysis was conducted to examine demographic characteristics (gender, age, and education level) of the workers and occupation characteristics (monthly net earnings, employment type, occupation, working period up to now, workplace scale, type of work system, and weekly working hours). In order to find the work health issue ratio between the shift and non-shift work groups, logistic regression was analyzed and the association with health problems according to shift type by gender was looked at through cross-analysis. Results: According to the surveys conducted from the 1st KWCS (2006) to the 5th KWCS (2017), the proportion of shift workers continued to increase. Also, muscular pains in the lower limbs (hips, legs, knees, feet, etc.) (OR=1.135, 95%CI 1.031-1.251), headaches, eyestrain (OR=1.580, 95% CI 1.428-1.748), anxiety (OR=1.715, 95% CI 1.402-2.099), difficulty falling asleep (OR=1.391), and other problems (OR=7.392) were reported. In addition, back pain, muscular pains in shoulders, neck and/or upper limbs, muscular pains in lower limbs (hips, legs, knees, feet, etc.), headaches, eyestrain, depression, anxiety, overall fatigue resulted in significant results for both male and female shift workers. Depression and anxiety were higher in female shift/circulation compared to males. Conclusions: The social nets for the health and safety of shift workers should be explored in a variety of ways, including management and supervision of shift sites, attempts to reorganize and improve the shift system, development of workers' health recovery programs, promotion, systematic treatment, and compensation systems.

• Journal of Internet Computing and Services
• /
• v.6 no.2
• /
• pp.69-84
• /
• 2005

As the Internet users are increasing rapidly, a cluster web server system is attracted by many researchers and Internet service providers. The cluster web server has been developed to efficiently support a larger number of users as well as to provide high scalable and available system. In order to provide the high performance in the cluster web server, efficient load distribution is important, and recently many content-aware request distribution techniques have been proposed. In this paper, we propose a new content-aware load balancing technique that can evenly distribute the workload to each node in the cluster web server. The proposed technique is based on the hash histogram transformation, in which each URL entry of the web log file is hashed, and the access frequency and file size are accumulated as a histogram. Each user request is assigned into a node by mapping of (hashed value-server node) in the histogram transformation. In the proposed technique, the histogram is updated periodically and then the even distribution of user requests can be maintained continuously. In addition to the load balancing, our technique can exploit the cache effect to improve the performance. The simulation results show that the performance of our technique is quite better than that of the traditional round-robin method and we can improve the performance more than $10\%$ compared with the existing workload-aware load balancing(WARD) method.

• Journal of Internet Computing and Services
• /
• v.6 no.2
• /
• pp.141-152
• /
• 2005

Many organizations have been recognizing the necessity of workflow automation technologies according to the rapid expansion of business process oriented applications, such as enterprise resource pianning, customer relationship management, electronic approval management, and so on, Thus, they have started adopting workflow management systems as an essential technological solution for their workflow processes, However, we need some technological extensions and improvements on them in order to accommodate a new type of workflow processes, which is called cross-organizational global workflow processes that require a certain level of collaborations between the organizations engaged in the global workflow processes, Fragment-driven workflow modeling methodology is a Bottom-Up methodology composing a global workflow by defining each organization's own activities, which is called a fragment through a realtime cooperative system. The approach is able to not only simplify the modeling work but also keep each organization's independence in modeling a global workflow, In this paper, we describe the fragment-driven workflow modeling methodology and realize the methodology through the implementation of a cooperative swimlane workflow modeling system.

• Journal of the Korean Society for Library and Information Science
• /
• v.33 no.4
• /
• pp.65-83
• /
• 1999

This study is intended to build a cross-reference system as syndetic device to provide bibliographic relations and to collocate variant access points through references, by developing a reference record format. To this end, the method of this study are as follows: First, the roles of references, which have long been used in traditional records, have been reviewed. Second, ways in which references are depicted not only by current cataloging rules but also by authority control systems are examined. Major characteristics of the reference record are summarized as fellows: 1) If variations either of an author name or of a title are made, or any related works are published, only a single reference record is created. This record uses existing authority records, and instead of adopting authority headings, it will expand the function of the explanatory reference as well as newly implementing a relational reference which can later be used as a reference record. 2) All the variations of identical personal or group names and of lilies are dealt as one access point. In place of current 'see' and 'see also' references, not drawing lines between authority heading(1XX field), 'see'(4XX field) and 'see also' reference(5XX field), all forms of names will be simply applied to record field '1XX'. 3) Any form of data elements, which are used as access points, will be described in '1XX' which has equal value. When a need arises to explain relationships between various access points, it can be met by applying the general explanation reference-name(666 field). Similarly, when there is a need to articulate bibliographic relationships between related works, they will be suggested through the title and relational reference. 4) The title and relational reference regulates related terms that each relation type contains its field, according to each relational type, by reclassifying entire fields in order to provide direct bibliographic relation types on reference records. 5) Pointers which are connected to each access point present reference control numbers.

• The Journal of Korean Medicine
• /
• v.24 no.3
• /
• pp.165-171
• /
• 2003

Objective : Stroke is the second major cause of death in Korea. It is known that the survival and ultimate outcome in stroke depend on various factors, so it is not easy to predict unexpected death in stroke. This study was performed in order to find predicting factors of unexpected death in stroke. Methods : A retrospective study was accomplished by reviewing 21 medical records of stroke patients who expired in the ward of Kyung Hee Oriental Medical Center from January 1998 to December 2001. Data analyzed Were physical examination, laboratory findings, clinical charts and APACH III scoring system. Results : I. The number of unexpected deaths at the ward of Kyung Hee Oriental Medical Center from January in 1998 to December in 2001 were 21 patients (0.1%). 2. Major risk factors of unexpected death were age (${\geq}60$), high blood pressure on 1st admission day and acute stage (${\leq}30{\;}days$). 3. The most frequent time of unexpected death was from 6 a.m. to noon. 4. Major cause of unexpected death was recurrence of stroke (40%). 5. APACH III scores of 75% of unexpected death patients were over 30 points. 6. Clinical change of symptoms 3 or 4 days before the unexpected death were dyspnea, change of urination and defecation. Conclusion; This mortality study suggests that old age, high blood pressure on 1st admission day, acute stage, and high APACH III score are the major predictors of unexpected death in stroke patients and that intensive medical attention is necessary to reach a better outcome.

• KSBB Journal
• /
• v.20 no.2 s.91
• /
• pp.112-115
• /
• 2005

E. coli in combination with bacteriophage $\lambda$ was used to overcome the intrinsic plasmid instability that is frequently found in recombinant fermentation especially in long-term operation. In order to enhance the stability and productivity, the bacteriophage ${\lambda}NM1070$ was used in this study. It is a $\lambda$ mutant, which is deficient in the synthesis of protein related to DNA packaging and cell lysis. The ${\lambda}NM1070$ is also a temperature-sensitive mutant. To optimize the production of recombinant protein in this temperature-sensitive system, the temperature effects on growth and cloned gene expression were investigated for stable and efficient recombinant gene expression. The induction to the lytic state was not complete at $36^{\circ}C$ while the temperature above $40^{\circ}C$ induced the lytic state completely. However, the productivity was decreased at $42^{\circ}C$ by temperature inhibition. The L-free cell concentration increased with the increase of temperature until $40^{\circ}C$. In conclusion, ${\lambda}NM1070$ has the optimal temperature at $38^{\circ}C$ for stability and at $40^{\circ}C$ for expression.

• Journal of Science and Technology Studies
• /
• v.12 no.2
• /
• pp.159-183
• /
• 2012

In order to create a desirable science culture needed in our society, it is necessary to overcome the foreignness of science and technology and to overcome severance from tradition. In this context, this article attempts to understand the characteristics of our traditional science and to explore the possibility of forming a desirable science culture through astronomy, which is an example of traditional science. Thus, this article examined the general characteristics of astronomy that had appeared first in ancient civilization. It also focused on the fact that each civilization has its own unique cultural elements together with astronomical knowledge as a field of science in traditional astronomy. Calendar and lifa(曆法), which are considered science of time, are closely connected with people's daily lives and reveal cultural differences clearly among the subfields of astronomy. In all ancient civilizations, time was represented based on the movements of the sun and the moon, but how time should be concretely represented varied, depending on different cultures. As a result, various calendar system emerged. Throughout East Asia, including our country, the luni-solar calendar was used. The calendar in East Asia, unlike that in the West, was the one derived from the lifa, which was very complex and elaborate astronomical work. The characteristics of the luni-solar calendar can be clearly found in the seasonal customs that represent people's daily lives well; however, lots of so-called superstition are also included in the seasonal customs. For this reason, it is easy to misunderstand that our calendar system is unscientific, or to suspect that our overall traditional science lacks scientific aspects. However, proper understanding of the calendar and the lifa of East Asia can confirm that scientific aspects certainly existed in our tradition. This will be the vital link to tradition that will help overcome the foreignness of today's science and technology.