• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.43 no.1
• /
• pp.7-15
• /
• 2020

It is a general phenomenon for manufacturers to provide vertically differentiated product line for more profit through improved market coverage. For such manufacturers, the compatibility between vertically differentiated products is an important decision issue. Some manufacturers provide full compatibility between high and low version products, whereas some provide only downward compatibility for the purpose of recommending high version product. In this study, the two representative compatibility strategies, full or downward, between vertically differentiated products produced by a single manufacturer are analyzed, especially under network externality and in the viewpoint of profit maximization. To do this we used a market model which captures the basic essence of vertical differentiation and network externality. Based on the proposed market model, the profit maximizing solutions are derived and numerically analyzed. The results can be summarized as follows : (1) Regardless of compatibility strategy, under network externality, vertical differentiation is always advantageous in terms of profit. (2) The full compatibility strategy is shown to be the most advantageous in terms of profit. In addition, it is necessary to make quality difference between differentiated products as wide as possible to maximize profit. (3) To gradually drive low version product out of the market and shift the weight pendulum of market to high version product, it is shown that the downward compatibility strategy is essential. Unlike intuition, however, it is also shown that in order to drive low version product out of market, it is necessary to raise the quality of the low version product rather than to lower it.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.9B
• /
• pp.760-773
• /
• 2003

The Internet is evolving from best-effort service toward an integrated or differentiated service framework with quality-of-service (QoS) assurances that are required for new multimedia service applications. Given this increasing demand for high bandwidth Internet with QoS assurances in the coming years, an IP/MPLS-based control plane combined. with a wavelength-routed dense-wavelength division multiplexing (DWDM) optical network is seen as a very promising approach for the realization of future re-configurable transport networks. This paper proposes a differentiated lambda establishment process for QoS guarantees based on the differentiated MPLS service (DMS) model. According to the QoS characteristics of wavelength in optical links and the type of used Optical Cross-Connect (OXC) nodes in DWDM next generation optical Internet backbone network, a differentiated wavelength assignment strategy that considers QoS recovery capability is also suggested.

• The Korean Journal of Cytopathology
• /
• v.14 no.1
• /
• pp.27-31
• /
• 2003

Poorly differentiated synovial sarcoma is a variant of synovial sarcoma. We report a case of poorly differentiated synovial sarcoma imprinted after resection. The patient was a 47-year-old woman with a right shoulder pain for 6 months. The cytologic features showed malignant round to oval, monotonous tumor cells with high nuclear to cytoplasmic ratio. Some tumor cells showed perivascular distribution and nuclear melding. Vague rosette-like structures were seen. On immunohistchemical stains, tumor cells were diffusely positive for CD99 and focally positive for epithelial membrane antigen. Ultrastructural examination showed desmosomes and microvilli.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.34 no.1
• /
• pp.39-59
• /
• 2009

Game theory is adapted to a variety of domains such as economics, biology, engineering, political science, computer science, and philosophy in order to analyze economic behaviors. This research is an application of game theory to wireless communication. In particular, in terms of bargaining game we dealt with a multimedia resource allocation problem in wireless communication, which is rapidly spreading such as Wibro, WCDML, IPTV, etc. The algorithm is assumed to allocate multimedia resources to users who can choose and access differentiated media services. For this purpose, 3 utility function of users is devised to reflect quality of service (QoS) and price. We illustrated experimental results with synthesis data which were made to mimic real multimedia data, and analyzed differentiated service providing and the effect of the utility function.

• Environmental and Resource Economics Review
• /
• v.11 no.3
• /
• pp.415-446
• /
• 2002

Due to its cost effectiveness, tradeable emission permits (TEP) system has been effectively used in the USA and many other advanced countries. But, academic many researchers have been argued that TEP system would not work as an efficient regulatory tools when there are imperfect competition in permits and/or products markets. Sartzetakis (1997), however, show that TEP system can serve as an effective environmental regulation under the certain demand/cost conditions even though duopolistic production market is not competitive. In this paper we extend Sartzetakis's analysis into the differentiated products markets under the same cost conditions, and examine the relative efficiency of TEP system by comparing it with the command and control system. We then show that the main results of Sartzetakis can hold if two differentiated products markets have the symmetric demands. In particular, it is revealed that social welfare will be increased under TEP system even though consumer surplus may be decreased.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2008.10a
• /
• pp.164-178
• /
• 2008

Game theory is adapted to a variety of domains such as economics, biology, engineering, political science, computer science, and philosophy in order to analyze economic behaviors. This research is an application of game theory to wireless communication. In particular, in terms of bargaining game we dealt with a multimedia resource allocation algorithm in wireless communication, which is rapidly spreading such as Wibro, WCDML, IPTV, etc. The algorithm is assumed to allocate multimedia resources to users who can choose and access differentiated media services. For this purpose, a utility function of users is devised to reflect quality of service (QoS) and price. We illustrated experimental results with synthesis data which were made to mimic real multimedia data, and analyzed differentiated service providing and the effect of the utility function.

• Korean Journal of Bronchoesophagology
• /
• v.17 no.2
• /
• pp.83-88
• /
• 2011

Robotic thyroidectomy has been developed to minimize neck scarring, and several authors have described its feasibility and safety, and have reported surgical outcomes comparable with conventional open thyroidectomy. The da Vinci surgical system robot provides a three-dimensional $10-12{\times}$magnified view of the surgical area. It also provides hand-tremor filtration, fine motion scaling, and precise and multi-articulated hand-like motions. Recently, robotic technology has also been applied to lateral compartment neck dissection in thyroid cancer. We have developed a new novel selective neck dissection procedure by a gasless unilateral axillo-breast (GUAB) approach with a da Vinci Surgical System for well-differentiated thyroid carcinoma to avoid a long visible neck scar. Based on our early experience, robotic selective neck dissection by GUAB approach is a safe, feasible and cosmetically excellent procedure. It can be an alternative to conventional open surgery in the highly selected patients with well-differentiated thyroid carcinoma. The oncologic safety of robotic selective neck dissection should be verified with long-term follow-up data.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.13
• /
• pp.5187-5190
• /
• 2015

This study aimed to investigate the correlation between ${\beta}$-catenin immunoexpression and histopathological grades of lower lip squamous cell carcinoma (LSCC). $\beta$-Catenin abnormal expression was found in 29% of the squamous cells of well differentiated LSCC, 63% of moderately differentiated and 86% of poorly differentiated, and therefor was significantly associated with histological grade (p=0.000). Nuclear $\beta$-catenin expression appeared in 5% of the cells and was also correlated with the histological grades (p=0.000). In 14.7% of the cells it was localized in the cytoplasm, again correlating with histology (p=0.002). According to this study the expression of $\beta$-catenin is an independent prognostic factor for histological grade and to the tumor differentiation. This appears to reflect a structural association and the role of $\beta$-catenin in tumor progression.

• 대한핵의학회:학술대회논문집
• /
• 2002.05b
• /
• pp.77-95
• /
• 2002

During the last several decades, prognosis of differentiated thvroid cancers improved markedly, mainly due to refinement of surgical techniques and routine use of radioactive iodine. Total or neat-total thyroidectomy is to be performed as the first line of treatment. Routine remnant ablation just after surgery decreases recurrence and increases survival. After then patients are maintained on suppressive dose of thyroid hormone to keep endogenous TSH below normal. Regular follow-up of the patients with serum thyroglobulin measurement and iodine whole body scan after thyroid hormone withdrawal or under recombinant human thyrotropin stimulation select high risk patients with recurrence or metastatic disease and treatment with therapeutic dose of radioactive iodine prolongs survival and sometimes leads cure. Currently recommended diagnostic and therapeutic strategies, present controversies and future directions are discussed.

• The Korean Journal of Nuclear Medicine
• /
• v.36 no.2
• /
• pp.140-142
• /
• 2002

A 67-year-old woman who had undergone anterior resection for a moderately differentiated adenocarcinoma of the rectum and wedge resection for liver metastasis presented with hematogenous lung metastasis. Metastatic pulmonary nodules in both lung fields were shown on plain chest radiograph and CT. Ga-67 SPECT images revealed accumulation of radioactivity corresponding to the pulmonary nodules. The authors present an unusual case of accumulation of Ga-67 in metastatic pulmonary nodules in a patient with a moderately differentiated adenocarcinoma of the rectum.