• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.6
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• pp.681-688
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• 2020

Approximately 6,000 chemicals are transported through the sea, including hazardous and noxious substances (HNS), which cause marine pollution and are harmful to marine life. The HNS discharged into the sea during the maritime transportation process undergoes physical and chemical changes on the sea surface and in seawater, and some types of HNS sink and are deposited on the seabed. The HNS deposited on the seabed adversely affects the benthic ecosystem, and hence, it is desirable to detect, treat, and recover the HNS on the seabed. Therefore, this study was conducted to analyze the performance requirements that should be considered as the top priority when developing a mechanical system for recovering the HNS deposited on the seabed. Various types of existing dredging devices used for collecting and recovering pollutants from river beds and seabeds were investigated, and 10 performance indices for the mechanical devices were selected. The new performance requirements for the development of the seabed-deposited HNS recovery system were proposed using performance indices. By considering the depth of water in domestic seaports, some of the performance requirements of the mechanical system for recovering deposited HNS from the seabed were obtained as follows: production rate (50-300 ㎥/hr), maximum operation depth (50 m), sediment type (most forms), percentage of solids (10 % or higher), horizontal operating accuracy (±10 cm), limiting currents (3-5 knots). These performance requirements are expected to be useful in the conceptual and basic design of mechanical systems for recovering seabed-deposited HNS.

• Journal of Advanced Navigation Technology
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• v.28 no.1
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• pp.109-115
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• 2024

The Concept of Operations (ConOps) document issued by the Korean Government (K-UAM ConOps) for urban air mobility (UAM) services takes into account not only aviation voice communication but also the use of 4G and 5G mobile communication to support the initial phase of UAM services. This paper studies a methodology to establish communication performance requirements for UAM traffic management and presents the analyzed results for communication performance requirements. To accomplish this, the operational scenarios of UAM developmental stages outlined in the K-UAM ConOps and FAA ConOps are scrutinized, and the diverse messages that must be communicated among various stakeholders for effective UAM operations are identified. A draft of communication performance requirements is also calculated by considering packet sizes, transmission frequencies, acceptable latencies, and availability. The outcomes of this study are expected to stand as a pioneering effort in defining communication requirements for UAM services, providing a crucial foundation for future initiatives such as the design of dedicated communication networks for UAM and the determination of required frequency bandwidth.

• Korean Journal of Construction Engineering and Management
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• v.7 no.2 s.30
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• pp.81-88
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• 2006

User's requirements are rapidly diversed by economic and social changes. Architect, however, doesn't well reflect user's required performance on the drawings in practical business, so that it causes many change orders. For this reason, this paper identified user's requirements through extensive literature review and convert users' requirements into the performance items in order to measure the weight through the survey from users and experts. The purpose of this paper is to provide a guidance for design through the comparing and analyzing the user's weight and expert's weight.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.9 no.1
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• pp.13-18
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• 2010

As the importance of non-functional requirements has increased, many researchers have become interested in the software development process for non-functional requirements including the notation, modeling, and assessment of non-functional requirements. However, the characteristics of non-functional requirements are so sophisticated and there are many topics which have not been solved until now. In order to address one of the unsolved problems, we propose a systematic software development process to support the management of non-functional requirements. The process consists of six steps, each of which is composed of detailed activities. Using the proposed process, the non-functional requirements can be managed and modeled more effectively and systematically than previous ones.

• Journal of electromagnetic engineering and science
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• v.13 no.4
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• pp.199-207
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• 2013

Meeting electromagnetic compatibility (EMC) requirements can be a significant challenge for engineers designing today's electronic devices. Traditional approaches rely heavily on EMC design rules. Unfortunately, these design rules aren't based on the specific EMC requirements for a particular device, and they don't usually take into account the specific function of the circuits or the many design details that will ultimately determine whether the device is compliant. This paper describes a design methodology that relates design decisions to the product's EMC requirements. The goal of performance-based EMC design is to ensure that electronic designs meet EMC requirements the first time the product is tested. More work needs to be done before this concept reaches its full potential, but electronic system designers can already derive significant benefit by applying this approach to products currently under development.

• Journal of Korea Multimedia Society
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• v.24 no.1
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• pp.51-57
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• 2021

In this paper, we propose a task distribution scheme in fog computing environment considering opportunistic fog computing nodes. As latency is one of the important performance metric for IoT(Internet of Things) applications, there have been lots of researches on the fog computing system. However, since the load can be concentrated to the specific fog computing nodes due to the spatial and temporal IoT characteristics, the load distribution should be considered to prevent the performance degradation. Therefore, this paper proposes a task distribution scheme which considers the static as well as opportunistic fog computing nodes according to their mobility feature. Especially, based on the task requirements, the proposed scheme supports the delay sensitive task processing at the static fog node and delay in-sensitive tasks by means of the opportunistic fog nodes for the task distribution. Based on the performance evaluation, the proposed scheme shows low service response time compared to the conventional schemes.

• Journal of Aerospace System Engineering
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• v.7 no.2
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• pp.29-34
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• 2013

Safety requirements for aircraft and system functions include minimum performance constraints for both availability and integrity of the function. These safety requirements should be determined by conducting a safety assessment. The depths and contents of aircraft system safety assessment vary depending on factors such as the complexity of the system, how critical the system is to flight safety, what volume of experience is available on the type of system and the novelty and complexity of the technologies being used. Requirements that are defined to prevent failure conditions or to provide safety related functions should be uniquely identified and traceable through the levels of development. This will ensure visibility of the safety requirements at the software and electronic hardware design level. This paper has prepared to study on promoting the efficiency of establishing hierarchical safety requirements from aircraft level function to item level through system safety processes.

• Journal of Navigation and Port Research
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• v.44 no.2
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• pp.110-118
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• 2020

With the expansion of the shipping and port logistics industry in the 21st century, the traffic density is continuously increased because of the increase in volumes of world sea freight and fleets, as well as the increase in the causes of potential marine accidents, such as ship collisions and stranding. Accordingly, the International Maritime Organization (IMO) has requested that the installation and operation of VTS should be applied in areas with high risk of marine traffic, and the request should be included as one of the Safety of Life at Sea (SOLAS) regulations. In this paper, the fundamental requirements of the radar system for vessel traffic services were analyzed and the analyzing factors were based on the IALA guideline.s This paper also includes results for the requirement and recommendation analysis on detection distance, target separation, and the target position accuracy of X-band radar. Also, to check if it satisfies the requirement of detection distance, range and azimuth separation of small point targets, and target position accuracy from the IALA guidelines, the test was conducted through the radar image acquired at the VTS center, and hence, the validity of the technical performance requirements was confirmed.

• Journal of Internet Computing and Services
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• v.5 no.6
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• pp.11-20
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• 2004

Proportional Fair (PF) share policy has been adopted as a downlink scheduling scheme in CDMA2000 l×EV-DO standard. Although It offers optimal performance in aggregate throughput conditioned on equal time share among users, it cannot provide a bandwidth guarantee and a strict delay bound. which is essential requirements of real-time (RT) applications. In this study, we propose a new scheduling policy that provides quality-of-service (QoS) guarantees to a variety of traffic types demanding diverse service requirements. In our policy data traffic is categorized Into three classes, depending on sensitivity of Its performance to delay or throughput. And the primary components of our policy, namely, Proportional Fair (PF), Weighted Fair Queuing (WFQ), and delay-based prioritized scheme are intelligently combined to satisfy QoS requirements of each traffic type. In our policy all the traffic categories run on the PF policy as a basis. However the level of emphasis on each of those ingredient policies is changed in an adaptive manner by taking into account the channel conditions and QoS requirements. Such flexibility of our proposed policy leads to offering QoS guarantees effectively and. at the same time, maximizing the throughput. Simulations are used to verify the performance of the proposed scheduling policy. Experimental results show that our proposal can provide guaranteed throughput and maximum delay bound more efficiently compared to other policies.

• Korean Journal of Agricultural Science
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• v.47 no.4
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• pp.783-789
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• 2020

This study was conducted to evaluate growth performance of weaned pigs using diets based on ideal protein of the Korea swine feeding standard (KFS) and US the nutrient requirements of swine (NRC). A total of 96 weaned (initial body weight of 6.12 ± 1.21 kg) pigs were randomly allocated into 2 dietary groups with 12 pens per diet (4 pigs·pen-1) in a completely randomized design. The dietary treatments were corn and soybean meal-based diets formulated by the KFS and NRC nutrient requirements estimates for weaned pigs. Experimental diets were fed for 6 weeks in 2 phases feeding program based on age: 1) Phase 1 = week 1 to 3 (21 days); 2) Phase 2 = week 4 to 6 (21 days). During Phase 1 and 2, there were no differences (p > 0.05) for the initial and final body weights between the KFS and NRC groups. Additionally, the average daily gain (ADG), average daily feed intake (ADFI), and gain to feed ratio (G : F) during overall experimental period were not different between the groups. In conclusion, weaned pigs fed the diet based on the KFS had a similar body weight and growth performance to those fed the diet based on the NRC. This suggests that the Korea swine feeding standard may be used for the diet formula of weaned pigs in Korea swine production compared with the US nutrient requirements of swine.