• Journal of Korean Tunnelling and Underground Space Association
• /
• v.21 no.5
• /
• pp.689-698
• /
• 2019

In tunnel excavation by TBMs, a cutterhead, which practically excavates the ground, is an important part directly affecting net penetration rate. Most of the researches on the cutterhead design that have been carried out until now are on the cutter arrangement. It is difficult to find a study for the effect of the scraper installation direction on TBM excavation although same cutterheads except for direction of the scraper are used in Korea. Therefore, this paper shows how the direction of scraper installation affects shield-TBM excavation. Discrete element method was used to identify the effect of scraper installation direction on shield-TBM excavation. When the scraper installation direction was outward, the amount of particles per unit time flowed into the cutter head opening was smaller than when the scraper installation direction was inward, and more loads were applied to the cutterhead.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2000.11a
• /
• pp.263-264
• /
• 2000

여과포 표면상에 도달하는 입자의 농토를 낮추거나 균일하게 유지시킬 경우, 부착된 입자층 두께의 성장으로 인한 압력손실의 증가율을 줄일 수 있고 이로 인하여 탈진 주기 또한 감소시킬 수 있다. 탈진조작의 저감으로 인하여 여과포의 수명 증대로 여과포의 교체 시기를 연장시킬 수 있으므로 여과포 집진장치의 운전 및 유지 보수비의 저감을 이룰 수 있다. 본 연구에서는 집진용기의 중간부분에 위치한 접선 유입관을 통하여 오염입자를 함유한 기체유동을 유입시킨 후, 원심력과 난류확산에 의하여 집진용기 내벽과 내통(inner tube) 벽면에 부착된 입자는 중력에 의하여 용기 바닥으로 모인 후 바닥면에 설치된 스크래퍼(scraper)를 통하여 분리 처리될 수 있는 새로운 형상의 집진장치를 개발하고자 하였다. (중략)

• Proceedings of the Korean Information Science Society Conference
• /
• 2003.10a
• /
• pp.199-201
• /
• 2003

멀티미디어 서비스는 미디어 오브젝트의 대용량 특성으로 인해 클라이언트에게 서비스를 수행할 때 QoS를 보장하기 어렵다. 이러한 문제를 해결하기 위한 많은 연구가 진행되었는데 이중 사용자의 요구에 대한 적절한 응답시간과 서버의 부하를 줄이기 위한 목적으로 주기적인 멀티캐스트가 제안되었다. 하지만 오브젝트를 세그먼트로 나누는 이 멀티캐스트 정책은 세그먼트 개수의 증가에 따라 서버의 작업부하가 커지게 되는 단점을 가진다. 따라서 본 논문에서는 주기적인 멀티캐스트를 수행하는 서버의 작업부하를 줄이기 위해 스카이스크래퍼 멀티캐스트와 하모닉 멀티캐스트를 통해 서버의 휴지시간을 유도하고, 이에 따라 서버가 멀티캐스팅하는데 이용되는 시간을 감소시키는 멀티캐스트 정책을 제안한다.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.20 no.5
• /
• pp.923-930
• /
• 2016

Various pipes are used in the many industrial field such as water supply, drainage system and marine plants, so a maintenance of these pipes is essential. Especially, the maintenance of the piping in the industrial field, some professional staffs enter and clean the pipe. If the professional staffs can not enter and clean the pipe, the workers has to use the method of inserting a scraper connected to wire inside the pipe. However, this method demands huge budget and causes a number of problems such as traffic congestion. To solve these problems, pipe cleaning robot has been researching and developing. Many Pipe cleaning robots have a problem, that is impossible to confirm the operating condition of the robot in a real time. This paper suggest pipe cleaning robot with RS-485 which transmit operating and cleaning condition of robot and inner pipe filmed by camera, that user can check.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.25 no.10
• /
• pp.1392-1399
• /
• 2001

The flow fields inside a molten Zn pot of continuous hot-chip galvanizing process were investigated experimentally. With varying several parameters including the strip speed Vs, flow rate Q of induction heater. scrapper location and baffle configuration, instantaneous velocity fields were measured using a PIV velocity field measurement technique. Inside the strip region, counter-clockwise rotating flow is dominant. The general flow pattern inside the strip region is nearly not influenced by the strip speed Vs, flow rate Q and the scrapper location. In the exit region, the flow separated from the moving strip due to the existence of a stabilizing roll ascends to the free surface, for the cases of no scrapper and scrapper detached form the roll. On the other hand, the ascending flow to the free surface is decreased, as the flow rate Q of induction heater increases. By installing a baffle around the uprising strip, the flow moving up to the stabilizing roll decreases. In addition, B-type baffle is better than A-type baffle in reducing speed of flow around the stabilizing rolls. However, the flow ascended to the free surface is largely influenced by changing the flow rate Q, and the scrapper location, irrespective of the baffle type.

• Journal of the Korean Geosynthetics Society
• /
• v.16 no.4
• /
• pp.163-176
• /
• 2017

The Discrete Element Method (DEM) has been widely used in civil engineering as well as various industrial fields to simulate granular materials. In this study, DEM was adopted to predict the performance of the face plate-type earth pressure balance (EPB) shield TBM (Tunnel Boring Machine). An analysis of the TBM excavation performance was conducted according to two pre-defined excavation conditions with the different rotation speeds per minute (RPM) of the cutterhead. The TBM model which was used in this study has a 6.64 m of diameter and six spokes. Also, 37 precutters and 98 scrapers at an each spoke were modeled with a real-scale specification. From the analysis, compressive forces at the cutterhead face, shield and cutting tools, resistant torques at the cutterhead face, muck discharge rate and accumulated muck discharge by the screw auger were measured and compared.

• Journal of Wetlands Research
• /
• v.16 no.3
• /
• pp.403-409
• /
• 2014

Assessment of pollutant loads for livestock manure based on total organic carbon (TOC) is being required to apply TOC as an indicator in management of total maximum daily loads. In this study, TOC based unit loads of pig manure known as highly contributing to water pollution assessed. The concentration of pig manure, amount of manure production including cleaning water, and unit loads were investigated targeting 52 farms according to 4 major river basins, rearing form, farm scale, and piggery form. The manure production was highly generated in scraper type of piggery, in small scaled farm rearing sow, and in Han River basin and Nakdong River basin. The averaged manure production was 7.4 L/head/d in total river basins. Averaged concentrations were investigated as TOC 16,037 mg/L, BOD 10,559 mg/L, TN 4,145 mg/L, and TP 503 mg/L. Corresponding unit loads were assessed as TOC 117.1 g/head/d, BOD 77.1 g/head/d, TN 34.7 g/head/d, and TP 3.67 g/head/d.

• Informatization Policy
• /
• v.31 no.1
• /
• pp.3-31
• /
• 2024

This study aimed to examine public concerns in South Korea considering the country's unique context, triggered by the advent of generative artificial intelligence such as ChatGPT. To achieve this, comments from 102 YouTube video news related to ethical issues were collected using a Python scraper, and morphological analysis and preprocessing were carried out using Textom on 15,735 comments. These comments were then analyzed using a Correlated Topic Model (CTM). The analysis identified six primary topics within the comments: "Legal and Ethical Considerations"; "Intellectual Property and Technology"; "Technological Advancement and the Future of Humanity"; "Potential of AI in Information Processing"; "Emotional Intelligence and Ethical Regulations in AI"; and "Human Imitation."Structuring these topics based on a correlation coefficient value of over 10% revealed 3 main categories: "Legal and Ethical Considerations"; "Issues Related to Data Generation by ChatGPT (Intellectual Property and Technology, Potential of AI in Information Processing, and Human Imitation)"; and "Fear for the Future of Humanity (Technological Advancement and the Future of Humanity, Emotional Intelligence, and Ethical Regulations in AI)."The study confirmed the coexistence of various concerns along with the growing interest in generative AI like ChatGPT, including worries specific to the historical and social context of South Korea. These findings suggest the need for national-level efforts to ensure data fairness.