• Journal of the Society of Disaster Information
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• v.16 no.2
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• pp.276-290
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• 2020

Purpose: The construction history of domestic port facilities has been more than 100 years, and until recently, modern facilities have been continuously built and expanded. However, it is not easy to keep the required performance conditions at the time of initial construction due to changes in the marine environment and increase in volume. In particular, in the case of harbor structures that have a long service life, safety performance and function management are becoming very important due to the increase in the size of ships, the increasing frequency of use, and the increase in the scale of natural disasters. Method: Therefore, this study investigates the state change by structural type of port facilities and analyzes the rehabilitation activities and the history that contribute to the performance improvement and life extension activities. Result: Through this, we distinguished between performance improvement cost (CAPEX) and repair maintenance activity (OPEX) that can be used to establish port facility maintenance strategy, and suggested cost model that can be used to establish maintenance strategy. Conclusion: These studies are expected to contribute greatly to mid- to long-term investment decisions.

• Korean Journal of Construction Engineering and Management
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• v.17 no.2
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• pp.12-20
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• 2016

Along with the change of national accounting, the importance of systematic management of assets is emphasized and the awareness that the concept termed Asset Management should be introduced to the construction field too to manage facilities. The present study is a basic study for the introduction of the concept Asset Management and proposed accounting guidelines(proposal) for public building maintenance cost that can clarify maintenance cost accounting. Existing literatures and current accounting standards were examined and the actual states of maintenance cost accounting of public buildings in A metropolitan city were examined to draw problems. For the practice guidelines(proposal), the types and contents of government office building maintenance expenditures were analyzed and items that must be treated as OPEX and CAPEX were presented. Expert interviews were conducted to verify the reliability of the items presented. The practice guidelines(proposal) were applied to the public buildings in A metropolitan city to identify situations of changes in asset values and review the effects of the practice guidelines(proposal) on increases in asset values. When applied to practices, the practice guidelines(proposal) suggested in the present study are considered to increase building asset values and provide consistent financial information to help stakeholders' decision making.

• Electronics and Telecommunications Trends
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• v.31 no.5
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• pp.90-98
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• 2016

컴퓨터 수준의 스마트 디바이스를 이용하는 현재의 이동통신 환경은 처리해야 할 정보량의 급속한 증가에 효율적으로 대응하기 위해서 새로운 시스템 및 네트워크 구조와 기술들을 연구개발하고 있고 여러 가지 후보 기술 중 대규모 고밀도 액세스 네트워크(UDN) 구조 연구에 대한 관심이 높아지고 있다. UDN 환경의 CAPEX 및 OPEX 문제를 해결하기 위해서 최근 액세스 네트워크의 공유 방안에 대한 논의 및 표준화가 진행되어 기술적으로는 인터넷 환경에서 검증된 가상화 기술의 액세스 네트워크 적용을 추진하고 있다. 이러한 동향을 반영하여 최근 SCF 주도로 완성된 소형 셀 기지국 가상화 규격이 현실적이고 실질적인 연구 결과로 평가되어 세부 사항을 분석한다.

• Journal of Ocean Engineering and Technology
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• v.33 no.6
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• pp.648-656
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• 2019

The ecological changes in the ocean due to the drastic global warming require that action be taken to sustain the productivity of fisheries. Proper ocean facilities could help prevent the loss of the expenditures made on marine aquaculture and reduce the related compensation for various ocean conditions. The aim of this study was to develop a floating ocean wave-breaker using an eco-friendly concrete and conducting a site survey, a structural analysis, and a test of towing the tank. As a result, the wave at the fish farm would be reduced. The results of the holding power of anchors and the capability of moving the floating structures were considered in the design of the wave-breaker. The analyses of the material properties of concrete and the steel structures, as well as the CAPEX and OPEX analyses of the manufacturing and operation processes confirmed the superiority of the floating concrete wave-breaker. In particular, this study demonstrated that the concrete floating breakwater can protect the fish farm against typhoons and reverse-waves, thereby reducing losses of the fish.

• Journal of KIISE
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• v.44 no.7
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• pp.719-725
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• 2017

To reduce management costs and improve performance, the European Telecommunication Standards Institute (ETSI) introduced the concept of network function virtualization (NFV), which can implement network functions (NFs) on cloud/datacenters. Within the NFV architecture, NFs can share physical resources by hosting NFs on physical nodes (commodity servers). For network service providers who support NFV architectures, an efficient resource allocation method finds utility in being able to reduce operating expenses (OPEX) and capital expenses (CAPEX). Thus, in this paper, we analyzed the network service chain embedding problem via an optimization formulation and found a close-optimal solution based on the Markov approximation framework. Our simulation results show that our approach could increases on average CPU utilization by up to 73% and link utilization up to 53%.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.5
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• pp.1319-1328
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• 2016

Since Ballast Water Management Convention has been effected, BWTS, applied to new-building vessels and existing vessels, have been developed from many countries with various treatment methods. However, BWTS is mainly typed Electrolysis, Ozone and UV type. Approximately 70 products have been type approved by the Flag Administrations. For the new-building vessels, the vessels' design and construction have been considered for arrangements and installations for BWTS. However, existing vessels which already construction had finished have problem with selection of BWTS type for installation and arrangement. The selection of the most economized BWTS system is important though, CAPEX has not been made any significant differences. However, OPEX is more important factor. Consequently, detail analysis of OPEX is the key to the selection of the most economized BWTS system and also it can be the purpose of this study. The feasibility study on the main three type of BWTS (Electrolysis, Ozone and UV type) for 175K Bulk Carrier and 57K Cargo ship has been conducted for this study. Because, these three type of BWTS have been the most frequently installed and used and the two type of object vessels are consist of the 40% of the world merchant ship market. For this study, interest rate, project duration (operation time after installation), maintenance cost and fuel oil price are considered as major factor of feasibility study. In addition, expecting Interest rates to sensitivity analysis conducted for more accurate feasibility study. For 175K Bulk carrier, ozone treatment system is more economical than other types. For 57K cargo ship, UV type is considered more economical than other types. However, it is concluded that electrolysis type is more suitable compare to installation space, total weight and electrical power consumption.

• Journal of the Korean Society of Mineral and Energy Resources Engineers
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• v.55 no.6
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• pp.624-634
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• 2018

Indonesia has become a net crude oil importer because of the reduction of a new oil field discovery, and Indonesia is attempting to raise investment funds through the Kerja Sama Operasi (KSO) contract to develop a small-scale field. However, the KSO has a high-risk and low-return contract system for investors, necessitating an economic evaluation to examine the feasibility of the project. This study performed economic evaluation on the development of an Indonesian small-scale field by applying the KSO contract conditions, and identified the major economic parameters through a sensitivity analysis. As a result, the oil price, CAPEX and OPEX were identified as influential factors for economic evaluation. The results also indicate that commercial production in small-scale fields is difficult. In the future, this study can be used as a reference resource for investment in oil and gas development projects in Indonesia.

• Clean Technology
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• v.29 no.1
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• pp.53-58
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• 2023

This study shows the summary of the economic performance of excess electricity conversion to hydrogen as well as methane and returned conversion to electricity using a fuel cell. The methane production process has been examined in a previous study. Here, this study focuses on the conversion of methane to electricity. As a part of this study, capital expenditure (CAPEX) is estimated under various sized plants (0.3, 3, 9, and 30 MW). The study shows a method for economic optimization of electricity generation using a fuel cell. The CAPEX and operating expenditure (OPEX) as well as the feed cost are used to calculate the discounted cash flow. Then the levelized cost of returned electricity (LCORE) is estimated from the discounted cash flow. This study found the LCORE value was ¢10.2/kWh electricity when a 9 MW electricity generating fuel cell was used. A methane production plant size of 1,500 Nm³/hr, a methane production cost of $11.47/mcf, a storage cost of $1/mcf, and a fuel cell efficiency of 54% were used as a baseline. A sensitivity analysis was performed by varying the storage cost, fuel cell efficiency, and excess electricity cost by ±20%, and fuel cell efficiency was found as the most dominating parameter in terms of the LCORE sensitivity. Therefore, for the best cost-performance, fuel cell manufacturing and efficiency need to be carefully evaluated. This study provides a general guideline for cost performance comparison with LCORE.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.3
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• pp.262-268
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• 2020

The IMO (International Maritime Organization) has mandated the restriction of SOx emissions to 0.5 % for all international sailing vessels since January 2020. And, a number of countries have designated emission control areas for stricter environmental regulations. Three representative methods have been suggested to cope with these regulations; using low-sulphur oil, installing a scrubber, or using LNG (Liquefied Natural Gas) as fuel. In this paper, economic analysis was performed by comparing the method of installing a scrubber with the method of using low-sulphur oil without installing additional equipment. We suggested plausible layouts and compared the pros and cons of dif erent scrubber types for retrofitting. We selected an international sailing ship as the target vessel and estimated payback time and benefits based on navigation route, fuel consumption, and installation and operation costs. Two case of oil prices were analyzed considering the uncertainty of fuel oil price fluctuation. We found that the expected payback time of investment varies from 1 year to 3.5 years depending on the operation ratio of emission control areas and the fuel oil price change.

• Electronics and Telecommunications Trends
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• v.28 no.6
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• pp.49-62
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• 2013

광-회선-패킷 통합 전달망 장비는 광전송망, 회선 망, 패킷 전달망 계층을 하나로 통합한 장비로써, 패킷-회선 교환 전달, ROADM(Reconfigurable Optical Add/Drop Multiplexer) 광파장 교환 전달, GMPLS(Generalized Multi-Protocol Label Switching) 기반 통합제어 및 관리기능을 수행하면서 네트워크 구조의 단순화, 네트워크 제어의 지능화, 그리고 네트워크 용량의 광대역화를 구현한다. 트래픽 폭증과 전송용량 부족 현상을 해결하고, 트래픽 증가 대비 수익의 탈동조화 현상을 극복하기 위해 네트워크 CAPEX(Capital Expenditures)/OPEX(Operating Expenditures)를 절감함으로써 통신사업자의 투자 여건을 우호적으로 조성하면서 최근 주목 받고 있는 기술이다. 본고에서는 광-회선-패킷 통합 전달망의 기술동향을 기술한 것으로써, 배경, 필요성 및 개념 개발동향 및 경쟁기술에 대해서 살펴보고, 기술발전 로드랩 및 주요 기술 동향과 시장 및 사업화 전망에 대해서 분석한다.