Most fishing nets used in fish cage aquaculture are made of synthetic fibers such as polyamide (PA) and polyethylene (PE). Therefore, it is challenging to maintain the internal volume of the fish cage due to biofouling, which can increase the load on the cage or reduce dissolved oxygen levels by impeding smooth current flow. To address this issue, research has been conducted to replace conventional synthetic fiber cage nets with brass nets, demonstrating certain benefits such as improved productivity and ease of fish cage management. However, given the need for a more thorough examination of brass fishing net weaving technology and performance, this study assessed the optimal weaving method for brass fishing nets to be used in fish cages. Additionally, it provided essential data for the practical application of brass fishing nets by evaluating their weight, tensile strength, elongation, fatigue resistance, and wear resistance. The study concluded that weaving brass fishing nets using the chain link method ensures durability, ease of installation, and compact storage in a scroll-like form. Moreover, due to their superior fatigue and wear resistance properties, brass nets can offer increased utility if appropriate net diameter and length are selected to compensate for their higher weight per unit area and relatively higher cost compared to existing fiber fishing nets.

Recently, the advancement of information and communication technology(ICT) is expanding the connectivity through Internet of Things(IoT), and the media of connection is also expanding from wire/cable transmission to broadband wireless communication, which has significantly improved mobility. This hyperconnectivity has become a key element of the fourth industrial revolution, whereas the supervisory control network of purification plants in korea is operated as a communication network separated from the outside, thereby lagging in terms of connectivity. This is considered the best way to ensure security, and thus there is hardly any consideration of establishing alternatives to operate an efficient and stable communication network. Moreover, security for management of a commercialized communication network and network management solution may be accompanied by immense costs, making it more difficult to make new attempts. Therefore, to improve the conditions for the current supervisory control network of purification plants, this study developed a industrial security L2 switch that supports modbus TCP(Transmission Control Protocol) communication and encryption function of the transmission section. As a result, the communication security performance improved significantly, and the cost for implementing the network management system using Historical Trend and information of HMI(Human Machine Interface) could be reduced by approximately KRW 200 million. The results of this study may be applied to systems for gas, electricity and social safety nets that are infrastructure communication networks that are similar to purification plants.

PURPOSES: To evaluate the feasibility of cut waste fishing net as a reinforced fiber for concrete. METHODS: Strength characteristics of fiber reinforced concrete using waste fishing net were investigated. The cut waste fishing nets with 4~5cm length were putted into the soil-cement and cement concrete for pavement slab. RESULTS: Compression and tensile strength of fiber reinforced concrete using waste fishing net were increased. CONCLUSIONS: It was concluded that cut waste fishing net can be used as a reinforced fiber for cement concrete. However, sometimes using cut waste fishing net leads to decrease the strength; therefore, further researches are needed for real project.

On the ultra-high speed broadband internet network transferring the massive multi-media data, the rapid restoration is very important. The online game industry is also fast growing with supporting of the real-time online network game. The online traffic on the internet network is steadily increasing. The optical based broadband convergence network provides these kinds of services. It is a form of multilayer network which loads the IP traffic on the lower optical DWDM. The failure of the link and node on this kind of network causes the significant loss of data. To solve this kind of problem, the new approach over the conventional one is necessary. It turned out to be its failure recovery thirty-five percent faster

현재 “어업”과 “납”과는 매우 밀접한 관계가 있으나, 어구에 사용되는 납의 환경 중 거동에 대한 체계적인 연구는 찾아볼 수 없는 실정이다. 2012년 9월 10일부로 시행된 ｢낚시관리 및 육성법｣에서는 낚시 도구라 지칭되는 모든 제품에 kg 당 납 성분이 90 mg이 초과하는 제품은 사용할 수 없도록 하고 있으나, 납은 비용적인 면에서나 가공의 수월성 면에서 어망에 많이 이용되고 있는 실정이다. 더욱이 어망의 폐기 실태, 어망 중 함유형태 및 함유량 등에 대한 자료는 찾아볼 수 없어 환경에서의 거동에 대한 검토는 전무하다. 이에 어구, 특히 폐어망에 함유된 납추의 환경 중 거동(fate)을 알아보기 위한 연구의 일환으로 수행하고 있는 본 연구에서는 우선, 어망에 함유된 납의 형태 (실납, 납추 등)를 알아보고, 함유 형태별, 환경 매체별 환경으로의 납 용출량을 알아보고자 하였다. 최근 발표된 일본의 “폐정치망 어망의 적정처리와 리사이클의 가능성으로의 과제 (2011년)”에서, 우선 납에 의한 오염이 확산되지 않도록 하기 위해서 어망과 로프에서 납추를 완전히 분리할 필요가 있으며, 그 분리 방법도 외부에 부착된 경우와 내부에 삽입된 경우와는 서로 다름을 보고하고 있다. 또한 분리된 어망과 로프는 화학적 리사이클이나 열회수 등으로 재활용하고, 분리한 납은 순도가 높아 판매가 가능하다고 생각되나, 실제로는 사용된 납추에는 조개류가 부착된 형태이므로 다른 적정처리가 필요함을 제기하고 있다. 폐어망 5kg을 분리･분별 장치에 넣고 납 분리를 실시한 결과, 로프 약 3kg, 납 약 1.5kg를 회수했으며, 나머지는 토사 등이었다고 보고하고 있다. 또, 4 종류의 폐어망의 납 함유량을 조사한 결과, 42.4 - 58.4% (무게비) 함유하고 있음을 확인하였으나, 납추 또는 실납 형태별 환경으로의 용출량에 대한 자료는 찾아볼 수 없었다.

최근 환경적 · 사회적으로 문제가 되고 있는 산업폐기물을 지반공학적 재료로 재활용하기 위한 관심이 확대대고 있는 추세이다. 따라서 본 연구에서는 화력발전소의 대표적인 산업부산물인 석탄회 중 저회의 도로 성토용 재료 및 구조물 뒤채움용 재료로의 이용을 위해 폐어망보강 저회의 CBR 특성을 분석하였다. 폐어망의 보강 방법은 지오그리드와 같은 층보강 형태, 그리고 단섬유처럼 불특정보강 형태를 이용하였고, 지지력 시험 결과 CBR 값은 짧게 잘라서 랜덤하게 혼합한 경우보다 층으로 보강하였을 때 더 높은 결과 값을 나타내었다. 또한 보강 층수가 증가할수록 보강효과도 증가하는 경향을 보였다.

Radar is an indispensible equipment in all vessels under way. In Korea there are many fishing net buoys near the coast, which causes an enormous threat to safe navigation because it is very difficult to detect the buoys by radar due to their small radar cross section. In this study RTE(Radar Target Enhancer) was installed on the fishing net buoy and its echo was analysed carefully. The results showed the possibility of wide detection of targets, especially small targets such as fishing net buoys, navigation buoys and etc.