• The Korean Journal of Applied Statistics
• /
• v.31 no.1
• /
• pp.109-122
• /
• 2018

The composite lognormal-generalized Pareto distribution (LN-GPD) is a mixture of right-truncated lognormal and GPD for a given threshold value. Scollnik (Scandinavian Actuarial Journal, 2007, 20-33, 2007) shows that the composite LN-GPD is adequate to describe body distribution and heavy-tailedness. This paper considers time-varying modeling of the LN-GPD based on local polynomial maximum likelihood estimation. Time-varying model provides significant detailed information of time dependent data, hence it can be applied to disciplines such as service engineering for staffing and resources management. Our work also extends to Beirlant and Goegebeur (Journal of Multivariate Analysis, 89, 97-118, 2004) in the sense of losing no data by including truncated lognormal distribution. Our proposed method is shown to perform adequately in simulation. Real data application to the service time of the Israel bank call center shows interesting findings on the staffing policy.

• Journal of KIISE:Computing Practices and Letters
• /
• v.9 no.4
• /
• pp.410-419
• /
• 2003

The buffer cache of general operating systems such as Linux manages file data by using global block replacement policy and read ahead. As a result, multimedia data with a low locality of reference and various consumption rate have low cache hit ratio and consume additional buffers because of read ahead. In this paper we have designed and implemented a new buffer allocation algorithm for multimedia data on Linux. Our approach keeps one read-ahead cache per every opened multimedia file and dynamically changes the read-ahead group size based on the buffer consumption rate of the file. This distributes resources fairly and optimizes the buffer consumption. This paper compares the system performance with that of Linux 2.4.17 in terms of buffer consumption and buffer hit ratio.

• Journal of KIISE:Computer Systems and Theory
• /
• v.33 no.3
• /
• pp.193-204
• /
• 2006

In most existing distributed Web systems, incoming requests are distributed to servers via Domain Name System (DNS). Although such systems are simple to implement, the address caching mechanism easily results in load unbalancing among servers. Moreover, modification of the DNS is necessary to load considering the server's state. In this paper, we propose a new dynamic load balancing method using dynamic DNS update and round-robin mechanism. The proposed method performs effective load balancing without modification of the DNS. In this method, a server can dynamically be added to or removed from the DNS list according to the server's load. By removing the overloaded server from the DNS list, the response time becomes faster. For dynamic scheduling, we propose a scheduling algorithm that considers the CPU, memory, and network usage. We can select a scheduling policy based on resources usage. The proposed system can easily be managed by a GUI-based management tool. Experiments show that modules implemented in this paper have low impact on the proposed system. Furthermore, experiments show that both the response time and the file transfer rate of the proposed system are faster than those of a pure Round-Robin DNS.

• Journal of KIISE
• /
• v.43 no.3
• /
• pp.275-288
• /
• 2016

In this paper, we investigate the security issues of the Android platform which dominates the global market of smart mobile devices. The current permission model for Android security is not powerful and has two problems. One is the coarse-grained relationship between permissions and methods which require them. The other is that mobile users do not have rights to control the permissions of the application. To solve these problems, we propose MacDroid which can control the platform's resources for accessing installed applications. Users can control the application's behavior via MacDroid's policy. We have divided the permission set into method units. The results of the performance test using a pure Android platform show that our proposed scheme can improve security within a short time.

• Journal of Korean Society for Quality Management
• /
• v.31 no.3
• /
• pp.62-84
• /
• 2003

The typical reason of the private sector's increasing share in standardization is that the procedures of official standardization organizations are out of step with the rate of technical development. At today's so fast pace that the success of a technology is decided in the market even before it is standardized, several industry leaders jointly make their draft standard at the early stage of development, which becomes 'De fecto Standard.' To respond effectively to current trends of standardization where the market's decision is thought much of than official standardization procedures, it is necessary to shift from our current public sector-driven to private sector-driven standardization. Therefore, to vitalize the private sector-driven standardization in Korea, there is a need to: Run a standard foundation to secure stable resources for standardization Make information exchange between the govertment and private sector active and policy-making on standards consistent by designating a private organization to cover the roles, policies on standards, and support of the national standardization organization Establish a system to make private sector-driven standards approved as international standards Offer a training program to forster standard experts Publicize the importance of standards Promote standardization forums driven by private businesses, like the Integrated Forum. Maximize the benefits of linking standards and patents Now, Korea is on the threshold of developing into a world-class standard leader, and the private sector-driven standardization should be a stepping-stone for crossing over the threshold. This study is designed to suggest a method of promoting private sector-driven standardization to effectively cope with fast-changing international standards, based on the cases in developed countries.

• Architectural research
• /
• v.9 no.2
• /
• pp.27-35
• /
• 2007

Our nation has a problem with discrimination of income distribution and inefficient of resources distribution caused by real estate price rising from a sudden economy growth and industrialization. Specially, in recent years, there is a great disparity of apartment price between the north and south of the Han river. Because the housing price is decided by the immanent value of a house and neighborhood effects of the regional where the house is situated, the housing price is occurred difference. The purpose of study was to analyze the influence of various factors of housing price. Also, this study tried to predict real estate market and to establish previous effective real estate policy. In this study, we analyzed the differences of housing price determinants about apartment developments between the north and south of the Han river, and found the important factors that affect the housing price using Structural Equation Modeling(SEM). As a result of this study, the older the buildings are, the more the housing price and the housing price rising ratio have increased, in Gang Nam area. This reason is that these have large possibility to be reconstructed and many convenient facilities, in this area. In the case of Kang Buk area, the increase rate of housing price are so low that they couldn't take effect on the housing price and they were declined. So to speak, constructing the infrastructure which takes effect on the increase rate of housing price is very urgent.

• Knowledge Management Research
• /
• v.17 no.3
• /
• pp.65-91
• /
• 2016

Although the success of industrial clusters largely depends on whether clustering firms can achieve economic performance, there has been less attention on investigating factors and conditions contributing to the performance enhancement for clustering small and medium-sized enterprises (SMEs). Along this vein, we adopt the theories of social capital and organizational learning as those success factors for clustering SMEs. This study thus aims at examining what effect social capital accrued in the relationships among actors within clusters has on firm performance of clustering SMEs and what role organizational learning plays in the linkage between social capital and firm performance. For the empirical analysis, we operationalized the variables and their measures to develop questionnaires through the theoretical reviews on literatures. As a sample of 227 clustering SMEs, our collected data was analyzed by hierarchical regression analysis. The results confirmed that a high level of social capital, represented by network, trust, and norm, has positive effect on firm performance of clustering SMEs. We also found that clustering firms presenting high organizational learning, represented by absorptive and transformative capability, achieve better performance than those placing less value on organizational learning. Furthermore the significant relationship between social capital and firm performance is mediated partially through organizational learning. These findings imply not only that the territorial agglomeration of industrial cluster does not guarantee the performance creation of clustering SMEs but that they need to develop social capital among various actors within clusters, facilitating their knowledge diffusion. In order to absorb and mobilize the shared knowledge and information into strategic resources, the firms should improve their capability associated with organizational learning. These expand our understanding on the importance of social capital and organizational learning for the performance enhancement of clustering firms. Differentiating from major studies addressing benefits and advantages of industrial cluster, this study based on the perspective of firm-internal business process contributes to the literature advancement. Strategic and policy implications of this study are discussed in detail.

• The Korean Journal of Applied Statistics
• /
• v.27 no.3
• /
• pp.387-396
• /
• 2014

The GDP gap (also called the output gap) is the difference between potential GDP and actual GDP. Potential GDP is the maximum sustainable output that is achieved when the resources (labor and capital) are used to capacity. Central banks pursuing price and employment stability consider the output gap as an informative variable for monetary policy since the output gap could be regarded as a proxy of demand-supply imbalances. In this paper, the GDP gap of Korea is decomposed following the filtering method in the previous research, and major factors that affect the variation of GDP gap are investigated based on the decomposed series. The analysis results by the Super Smoother algorithm used in Fox et al. (2003)and Fox and Zurlinden (2006) are found consistent with theory. Much of the variation of nominal GDP gap is explained by Total Factor Productivity(TFP) gap, which is the change of productivity due to recent technological innovation and environmental change. It is also found that variation of terms of trade significantly affects the GDP gap of Korea due to its high dependency on international trade; however, the effect of the domestic price is not negligible like other countries.

• Journal of Digital Convergence
• /
• v.15 no.10
• /
• pp.133-150
• /
• 2017

In this study, the performance of the technological innovation of small and medium enterprises is divided into short-term aspects of technological innovation and long-term aspects of ambidextrous innovation, and the effects of dynamic capabilities affecting these achievements are explored. For the purpose of conducting empirical analysis, the survey conducted a survey of 219 small businesses belonging to various industries, and dynamic capabilities performed a parallel multi-parameter analysis to demonstrate the effectiveness of technological innovation performance, including exploratory innovation and exploitative innovation. Through this study, it aims to understand the dynamic capabilities of the small and midsize enterprises and provide suggestions on how to manage of the company, thereby improving the understanding of dynamic capabilities and helping to improve the management of small and medium-sized enterprises.

• Journal of Digital Contents Society
• /
• v.3 no.1
• /
• pp.47-57
• /
• 2002

Recently, wireless networks have been pursuing multimedia data service as voice, data, image, video and various form of data according to development of information communication technology. It guarantees cell delivery delay of real time data in efficient real time multimedia data transfer. Also, it minimizes cell loss rate of non-real time multimedia data. In the wireless ATM, there are based on Asynchronous Transfer Mode(ATM). It implies that there are various service with difficult transmission rates and qualities in the wireless communication network. As a result, it is important to find out the ways to guarantee the Quality of Service(QoS) for each kind of traffic in wireless network. In this thesis, we propose an improved TCRM scheduling algorithms for transmission real-time multimedia data service in wireless ATM Networks. We appear real time multimedia scheduling policy that apply each different method to uplink and downlik to wireless ATM network. It can guarantee QoS requirements for each real time data and non-real time data. It also deals the fairness problem for sharing the scarce wireless resources. We solve fault of TCRM as inefficient problem of non-real data by using arbitrary transmission speed and RB(Reservation Buffer) through VC(Virtual Control) and BS(Base Station).