• The Journal of the Acoustical Society of Korea
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• v.20 no.1
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• pp.43-49
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• 2001

EVRC (Enhanced Variable Rate Codec) has been adopted as a standard coder for the CDMA digital cellular system in North America and Korea, and known to provide good call quality at 8kbps. In this paper, fast implementation algorithms for EVRC encoder are proposed. The proposed algorithms are based on both efficient pitch detection scheme and fast fixed codebook search algorithm. In the codebook search, computational complexity is reduced down to 70％ of the original EVRC by limiting the number of pulse position combination and by using a truncated impulse response. The proposed algorithms enable us to implement the EVRC with much smaller computational works. Also, informal subjective tests confirmed that the difference in the speech quality between the original EVRC and the proposed method was indistinguishable.

• Journal of Communications and Networks
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• v.14 no.1
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• pp.15-20
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• 2012

As Internet protocol and wireless communications have developed, the number of different types of mobile services has increased gradually. Existing priority-computing schemes cannot satisfy the dynamic requirements of supporting multiple services in future wireless communication systems, because the currently used factors, mainly user priority, are relatively simple and lack relevancy. To solve this problem and provide the desired complexity, dynamic behavior, and fairness features of 3G and beyond 3G mobile communication systems, this paper proposes a novel cross-layer dynamic integrated priority-computing scheme that computes the priority based on a variety of factors, including quality of service requirements, subscriber call types, waiting time, movement mode, and traffic load from the corresponding layers. It is observed from simulation results that the proposed dynamic integrated priority scheme provides enhanced performance.

• Journal of the military operations research society of Korea
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• v.16 no.1
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• pp.18-34
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• 1990

In light of the recent developments of transitory nature, it is likely that national defense decision-making will be more difficult to make for years to come. In other words, sudden changes in security environment would call into question the basic assumptions on which we have built our national defense planning and increase the number of the uncertain factors in the decision-making process; the subdivision and ramification of national defense management would increase the factors for decision-making and complicate even further the mutual interactions among these factors; the accelerated pace of sophistication and diversification of weapon systems and military technology would increase the risk of failure and system costs geometrically; and the reduced level of acceptance among the people on the sanctification of national defense in proportion to the rapid progress toward a more democratic and industrial society would engender an increased criticism or checking role by the National Assembly or by the mass media. As the changes in national defense environment and conditions create an innumerable number of new tasks, this paper intends to suggest a few core policy measures to improve the quality of national defense decision-making. More specifically, it proposes to 1) eradicate entirely the bureaucratic behavior and tendencies; 2) utilize actively the brain staff for quality assurance of decision-making; 3) and introduce and apply as a whole set, a total system, or an incorporated pack age the PPBEES(Planning-Programming-Budgeting-Executing-Evaluating-System)/LCMM (Life-Cycle Management Model for System Acquision), the OR/SA(Operations Research/Systems Analysis), and DMIS (Defense Management Information System).

• Asia-Pacific Journal of Business
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• v.11 no.3
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• pp.21-46
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• 2020

Purpose - This study aims to find if the introduction of project finance perspective leads to any modification to the view of PM industry on CSFs of PPP and their relative importance rank. Design/methodology/approach - Through literature reviews, this study came up with a set of CSFs reflective of both perspectives. AHP method was applied for analysis by developing an Analytic Hierarchical Model from this set and survey questionnaires of pairwise comparison to solicit 46 qualified expert responses. Findings - This study concurs with PM industry to acknowledge 'risk allocation', 'legal framework' and 'quality of feasibility' as ones of most important CSFs. However, relative importance rank of individual CSFs goes through significant modification under this study in favor of 'sponsor commitment and quality' but against 'political environment', in particular. Research implications or Originality - Discussions on the CSFs led by PM industry have not been properly reflective of project finance perspective, which is injected into this study to cure the partiality. For researchers, findings of this study may call attention to financing perspective when they discuss CSFs of PPP. Practitioners may benefit from this study by allocating resources in view of this new finding when pursuing PPP projects.

• International Journal of Stem Cells
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• v.17 no.2
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• pp.113-119
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• 2024

This report presents guidelines for the systematic management of packaging, storage, transportation, and traceability of source cells used for organoid research. Given the important role of source cells in organoid studies, it is important to ensure the preservation of their quality and integrity throughout transportation and distribution processes. The proposed guidelines, therefore, call for a cohesive strategy through these stages to minimize the risks of contamination, deterioration, and loss-threats that significantly compromise the safety, efficacy, and efficiency of source cells. Central to these guidelines is the quality control measures that include roles and responsibilities across the entire supply chain, with recommendations specific to packaging materials, transportation facilities, and storage management. Furthermore, the need for an integrated management system is emphasized, spanning from source cell collection to the final application. This system is crucial for maintaining the traceability and accountability of source cells, facilitating the sharing, distribution, and utilization on a global scale, and supporting to advance organoid research and development.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.1
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• pp.68-78
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• 2013

In this paper, we propose an early spectrum sensing(ESS) as an advance preparation for radio-access trial, which enables multi-mode terminals to access the most appropriate radio-access system in a cloud-conceptual base station system where multiple radio access technologies(RATs) coexist. Prior to a random access to one of RATs, a multi-mode terminal conducts a spectrum sensing over entire frequency bands of whole RATs, then select the RAT with the lowest sensing power, that is likely to have the most available spectrum. Thus, an access failure caused by that the selected RAT has no available radio spectrum could be avoidable in advance. In computer simulation, we consider as various RATs as possible. First, circuit and packet systems are taken into consideration. In addition, the packet systems are classified according to the feasibility of carrier aggregation(CA). In case of terminal, three modes are considered with circuit-only, packet-only, and multi-mode. Subsequently, packet traffic is classified into real-time and non-real-time traffic with three different tolerable delay levels. The simulation includes a call process starting with a call generation and ending up with a resource allocation reflecting individual user's QoS requirements and evaluates the proposed scheme in terms of the successful access probability, system access time, system balancing factor and packet loss probability.

• Journal of Communications and Networks
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• v.1 no.3
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• pp.158-165
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• 1999

This paper studies interconnection of DCS1800 and GSM900 dual-band networks. Two types of interconnection config-urations for GSM services, non-overlap and overlap, are described. We propose analytic and simulation models to investigate the ben-efit of the overlap configuration. Our results explain how the radio channel capacities, the inter-system handoff failure rate, the origi-nating call traffic ratio and the offered loads affect the system per-formance. This study indicates that with appropriate overlap con-figuration, the GSM dual-band network can significantly improve the quality of cellular service.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.05a
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• pp.639-642
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• 2006

본 논문에서는 다양한 서비스가 운용되고 있는 인터넷 망에서 PCM 및 ADPCM으로 압축된 음성데이터를 전송할 경우에 발생하는 패킷 크기와 한계 지연시간의 변화가 수신측의 음질에 미치는 영향을 분석하였다. 이를 기반으로 주어진 한계 지연시간에 대하여 적절한 음질을 제공하기 위한 전송패킷의 크기에 대하여 분석하여 적절한 코덱 선택 방법을 제안하였다. 제안된 방법의 실험결과를 입증하기 위해 음질 평가인 MOS평가 방법을 사용했으며 측정방법으로는 서울을 중심으로 전국5개 지역 지점별 5회 측정 각 지점의 임의 번호를 서울 콜 센터로 Call Forwarding 설정 후 측정하고, VQT은 PAMS 알고리즘과 ADRA(Audio Direction Reference Audio)를 사용하여 측정한 결과 음성코덱의 데이터비와 Datagram size에 의해 음성 품질이 달라짐과 적절한 코덱 선택방법임을 확인하였다.

• Asia pacific journal of information systems
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• v.15 no.4
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• pp.27-60
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• 2005

The purpose of this study is to call attention to the consensus of stakeholders of corporate e-Learning system for the sake of its success. We identified the critical success factors(contents, technical features, management, and organizational support) as major components of corporate e-Learning systems and questioned whether stakeholders' consensus on the importance of these components facilitates the successful implementation of these components. We also questioned whether the influence of these components on user satisfaction could be moderated by contextual factors. Based on empirical testing of 18 e-Learning user companies, we verified that the consensus of stakeholders regarding the importance of content, technological features, and organizational support has a positive influence on the perceived quality of these factors in their e-Learning systems, which in turn is positively related to user satisfaction. The learning subjects and learning style did significantly moderate the influences of these perceived qualities on user satisfaction.

• The Korean Journal of Applied Statistics
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• v.10 no.1
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• pp.15-27
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• 1997

Randomized block design (RBD) with three replication is very frequently adopted in agricultural experiments of the Rural Development Administration of Korea. Even though it works well in field trials of traditional crops, it may not accomodate trial site conditions and/or experimental environment. In this research report, we deal with two such cases. The first case is for a crop experiment in green houses. In house conditions, RBD may not be appropriate since it cannot reflect two directions of the yield gradient. So, a Latin square design is suggested as an alternative. The second case is for local field experiments of the newly-inbred rice. RBD with three replications is used without doubt for decades, even though the site layout is not appropriately shaped for the design. In this case, we suggest the RBD in two blocks with multiple replicates for control varieties as an alternative. To improve the quality of statistical experimental designs in over one-thousand agricultural trials performed annually in the Rural Development Administration, we need to re-train agricultural researchers on the design and analysis of experiments and call for concerns of Korean statisticians.