• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.4C
• /
• pp.342-352
• /
• 2002

In this paper, we compare the performances of RIO and RIO-DC buffer management schemes for DiffServ AF PHB standardized in IETF. For the comparison, we relatively differentiate maximum delay for each Assured Service subclass in Differentiated Services by allocating bandwidth to each subclass differently. In addition, we set the values of RIO and RIO-DC parameters considering the buffer size determined by the network topology and the ratio of bandwidth allocated to each subclass. In this simulation environment, the performances of RIO and RIO-DC schemes are analyzed focusing on the throughput of the In-profile traffic, the link utilization and the fairness. Simulation results show that the performance of RIO-DC scheme is comparable to that of RIO scheme with regard to the throughput of the In-profile traffic and the link utilization. However, under the simulation condition RIO-DC scheme improves the fairness between flows much better than RIO scheme.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.40 no.3
• /
• pp.66-75
• /
• 2017

Priority disciplines are an important scheme for service systems to differentiate their services for different classes of customers. (N, n)-preemptive priority disciplines enable system engineers to fine-tune the performances of different classes of customers arriving to the system. Due to this virtue of controllability, (N, n)-preemptive priority queueing models can be applied to various types of systems in which the service performances of different classes of customers need to be adjusted for a complex objective. In this paper, we extend the existing (N, n)-preemptive resume and (N, n)-preemptive repeat-identical priority queueing models to the (N, n)-preemptive repeat-different priority queueing model. We derive the queue-length distributions in the M/G/1 queueing model with two classes of customers, under the (N, n)-preemptive repeat-different priority discipline. In order to derive the queue-length distributions, we employ an analysis of the effective service time of a low-priority customer, a delay cycle analysis, and a joint transformation method. We then derive the first and second moments of the queue lengths of high- and low-priority customers. We also present a numerical example for the first and second moments of the queue length of high- and low-priority customers. Through doing this, we show that, under the (N, n)-preemptive repeat-different priority discipline, the first and second moments of customers with high priority are bounded by some upper bounds, regardless of the service characteristics of customers with low priority. This property may help system engineers design such service systems that guarantee the mean and variance of delay for primary users under a certain bounds, when preempted services have to be restarted with another service time resampled from the same service time distribution.

• Journal of Korean Society for Quality Management
• /
• v.33 no.3
• /
• pp.1-18
• /
• 2005

Internal marketing has been suggested as the approach for service organizations to be service-and customer-oriented; and the issues of internal service quality has been one of topics widely discussed in the internal marketing literature. The purpose of the current study is to examine the antecedents and consequences of internal service quality which is believed to increase such organizational performances as customer satisfaction, retention and revenue. In consistent with the previous studies in service marketing literatures, the current study identifies several constructs as the antecedents and consequences of internal service quality: management commitment to service quality, employee satisfaction, self-efficacy, and adaptability. The empirical study testing the causal relationships' among the constructs verifies the proposed relationships among the constructs suggested in the current study.

• ETRI Journal
• /
• v.34 no.4
• /
• pp.492-502
• /
• 2012

We consider an overlaid broadcast service, where a spread spectrum (SS)-based broadcast signal is overlaid onto the existing terrestrial Digital Multimedia Broadcasting (T-DMB) band. The system is similar to the augmented data transmission in the ATSC DTV, for which it was investigated mostly in terms of link level performance, such as bit error rate. Our focus in this paper is on the system-level performances. More specifically, utilizing both a large scale path loss and a small scale fading channel model, the primary objective is to explore the tradeoff between the coverage and the achievable rate of the overlaid service and, finally, to determine the achievable rate in the overlaid service for marginal coverage reduction in the existing broadcast service. The analytical and simulation results show that an SS-based add-on service of 10 kbps to 20 kbps can co-exist with the T-DMB service while resulting in only a marginal degradation in T-DMB coverage (for example, less than one percent reduction).

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.7A
• /
• pp.467-476
• /
• 2003

In this paper, we propose an efficient MAC scheduling algorithm for supporting Bluetooth scatternet operations. Our proposed algorithm improves overall performances of scatter mode［2, 3] and considers QoS requirements of each link of the bridge node of a scatternet. Scatter mode is based on time division scheduling and provides every links of a scatternet with fair service opportunities. However, since each Bluetooth devices has various traffic characteristics. fair allocation of service opportunities is not efficient and may cause extravagance of wireless resources. Therefore, we propose a new efficient inter-piconet scheduling algorithm compliant with the current Bluetooth specification［1］, and demonstrate its improved performances via computer simulations.

• Journal of the Economic Geographical Society of Korea
• /
• v.9 no.2
• /
• pp.181-196
• /
• 2006

This study analyzed the inter-regional productivity performance of Southeast region of Korea, namely, Busan, Daegu, Ulsan, Gyeongbuk, and Gyeongnam for 16 service sectors, which are categorized by two groups, knowledge based service (5 sectors) and non-knowledge based one (11 sectors) for the period of 1997-2004. This study applied the method of Malmquist productivity change index(MPI) to the estimation of spatial productivity. According to the estimation results, firstly, the MPI of service sector has been deteriorated by annually 0.1% on average. However, when we divided the period into 1997-2000 and 2001-2004, the productivity performances of the second period was better than that of the first period, which are the same trend in knowledge based and non-knowledge based service sectors. Secondly, comparing productivity performances by region and sector during the whole period, Daegu has seven sectors which are relatively comparative advantage. and Ulsan and Busan have six and five sectors, respectively, which are relatively comparative advantage.

• Korean Journal of Social Welfare
• /
• v.65 no.4
• /
• pp.115-136
• /
• 2013

This research purports to examine the mediating effects of right perception and performance at service processes in relationship to the social worker's professionalism and user advocacy. As the research method, 198 social workers were surveyed, and structural equation was used for analysis. The research findings showed that the professionalism of social workers had a direct influence on right perception, right performances at service processes and user-advocacy. However, right perception at service processes do not have a direct influence on user advocacy. In addition to this right perception and performances at service processes was proven to be an important mediator between a social worker's professionalism and user advocacy. As a result, this research has implied the necessity for social work practice to promote user-advocacy.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.7
• /
• pp.2909-2920
• /
• 2012

The roles of public and private employment service agencies have been considered crucially important due to the increasing interest of employment services and policies since the Korean Currency Crisis. Eventually, the roles of a manager and a follower of employment service agencies have been of greater importance. In this study, several means concerning the improvement in organizational performances are suggested by studying the leadership's influence of a team leader in employment service agency over the organizational commitment of the followers. In addition to this, influential factors exerted to the organizational performances in an employment service agency have been analysed by the justice awareness between the two groups - team leaders and followers. The analytic results have shown that the transactional leadership has nothing to do with the organizational commitment whereas the transformational leadership has the positive influence over the organizational commitment. However, the leadership of a leader surely influences both distributional and procedural justice. With these facts, it has been proven that these justice have also influenced on the organizational committment. Throughout the process, it has been identified that the distributional justice has more impact on the organizational commitment rather than on the procedural justice.

• International Commerce and Information Review
• /
• v.14 no.4
• /
• pp.275-295
• /
• 2012

Korea's economic development started from early 1960s over war devastation. Korean government drove promoting export with its all efforts. In 2011, Korea joined the "USD 1 trillion trade club" as the 9th nation in the world. It is true that the growth of Korean exports has greatly contributed to the development of Korean economy, and that workers in the export promoting organizations also contributed to such a tremendous performance. Still, there are a number of SMEs waiting for more support from the export promoting organizations. This paper tried to identify the determinants of organizational performances of export promoting organization workers with particular focus on their public service motivation and self-esteem. Our findings are as follows; Workers' public service motivation and self-esteem are strongly related to their organizational commitment, job satisfaction, organizational performances. In addition, the workers show a different level of intrinsic and extrinsic satisfaction when it comes to public service and customer satisfaction. This reflects the employees of export promoting organizations have more focused on the value and accomplishment of their performances in workplace. Women and younger workers within the organizations tend to have weaker organizational commitment. In conclusion, we recommend that it is important to increase the women's organizational commitment and develop more inspirational personnel programs to younger workers within the organizations in order to support Korea's promising SMEs in a more practical manner.

• Journal of the Korean Society of Physical Medicine
• /
• v.5 no.3
• /
• pp.421-434
• /
• 2010

Purpose : The purpose of this study is to understand the attitudes to internal service quality between coworkers, service quality to patients, job satisfaction, organizational identification and job identification of physical therapists in medical organizations. Methods : Data were collected from physical therapists working in medical organizations. 195 questionnaires were analyzed. Participants' total mean, group mean by age, sex, career and type of medical organization and the variables' correlations were examined. Results : The attitudes of physical therapists to five variables were very positive. Especially job identification was strong. The significant differences between groups were found in some variables. All variables except age and career were positively related to each other. The correlation between age and career was very high. Age and career were related to some of variables. Conclusion : To improve organizational performances it should be a top priority to understand the attitudes of physical therapists in organizations.